Task
Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero.
In Roman numerals:
- 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC
- 2008 is written as 2000=MM, 8=VIII; or MMVIII
- 1666 uses each Roman symbol in descending order: MDCLXVI
ActionScript
function arabic2roman(num:Number):String {
var lookup:Object = {M:1000, CM:900, D:500, CD:400, C:100, XC:90, L:50, XL:40, X:10, IX:9, V:5, IV:4, I:1};
var roman:String = "", i:String;
for (i in lookup) {
while (num >= lookup[i]) {
roman += i;
num -= lookup[i];
}
}
return roman;
}
trace("1990 in roman is " + arabic2roman(1990));
trace("2008 in roman is " + arabic2roman(2008));
trace("1666 in roman is " + arabic2roman(1666));
1990 in roman is MCMXC
2008 in roman is MMVIII
1666 in roman is MDCLXVI
And the reverse:
function roman2arabic(roman:String):Number {
var romanArr:Array = roman.toUpperCase().split('');
var lookup:Object = {I:1, V:5, X:10, L:50, C:100, D:500, M:1000};
var num:Number = 0, val:Number = 0;
while (romanArr.length) {
val = lookup[romanArr.shift()];
num += val * (val < lookup[romanArr[0]] ? -1 : 1);
}
return num;
}
trace("MCMXC in arabic is " + roman2arabic("MCMXC"));
trace("MMVIII in arabic is " + roman2arabic("MMVIII"));
trace("MDCLXVI in arabic is " + roman2arabic("MDCLXVI"));
MCMXC in arabic is 1990
MMVIII in arabic is 2008
MDCLXVI in arabic is 1666
Ada
with Ada.Text_IO; use Ada.Text_IO;
procedure Roman_Numeral_Test is
function To_Roman (Number : Positive) return String is
subtype Digit is Integer range 0..9;
function Roman (Figure : Digit; I, V, X : Character) return String is
begin
case Figure is
when 0 => return "";
when 1 => return "" & I;
when 2 => return I & I;
when 3 => return I & I & I;
when 4 => return I & V;
when 5 => return "" & V;
when 6 => return V & I;
when 7 => return V & I & I;
when 8 => return V & I & I & I;
when 9 => return I & X;
end case;
end Roman;
begin
pragma Assert (Number >= 1 and Number < 4000);
return
Roman (Number / 1000, 'M', ' ', ' ') &
Roman (Number / 100 mod 10, 'C', 'D', 'M') &
Roman (Number / 10 mod 10, 'X', 'L', 'C') &
Roman (Number mod 10, 'I', 'V', 'X');
end To_Roman;
begin
Put_Line (To_Roman (1999));
Put_Line (To_Roman (25));
Put_Line (To_Roman (944));
end Roman_Numeral_Test;
MCMXCIX
XXV
CMXLIV
ALGOL 68
[]CHAR roman = "MDCLXVmdclxvi"; # UPPERCASE for thousands #
[]CHAR adjust roman = "CCXXmmccxxii";
[]INT arabic = (1000000, 500000, 100000, 50000, 10000, 5000, 1000, 500, 100, 50, 10, 5, 1);
[]INT adjust arabic = (100000, 100000, 10000, 10000, 1000, 1000, 100, 100, 10, 10, 1, 1, 0);
PROC arabic to roman = (INT dclxvi)STRING: (
INT in := dclxvi; # 666 #
STRING out := "";
FOR scale TO UPB roman WHILE in /= 0 DO
INT multiples = in OVER arabic[scale];
in -:= arabic[scale] * multiples;
out +:= roman[scale] * multiples;
IF in >= -adjust arabic[scale] + arabic[scale] THEN
in -:= -adjust arabic[scale] + arabic[scale];
out +:= adjust roman[scale] + roman[scale]
FI
OD;
out
);
main:(
[]INT test = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,25,30,40,50,60,69,70,
80,90,99,100,200,300,400,500,600,666,700,800,900,1000,1009,1444,1666,1945,1997,1999,
2000,2008,2500,3000,4000,4999,5000,6666,10000,50000,100000,500000,1000000,max int);
FOR key TO UPB test DO
INT val = test[key];
print((val, " - ", arabic to roman(val), new line))
OD
)
{{out}} (last example is manually wrapped):
+1 - i
+2 - ii
+3 - iii
+4 - iv
+5 - v
+6 - vi
+7 - vii
+8 - viii
+9 - ix
+10 - x
+11 - xi
+12 - xii
+13 - xiii
+14 - xiv
+15 - xv
+16 - xvi
+17 - xvii
+18 - xviii
+19 - xix
+20 - xx
+25 - xxv
+30 - xxx
+40 - xl
+50 - l
+60 - lx
+69 - lxix
+70 - lxx
+80 - lxxx
+90 - xc
+99 - xcix
+100 - c
+200 - cc
+300 - ccc
+400 - cd
+500 - d
+600 - dc
+666 - dclxvi
+700 - dcc
+800 - dccc
+900 - cm
+1000 - m
+1009 - mix
+1444 - mcdxliv
+1666 - mdclxvi
+1945 - mcmxlv
+1997 - mcmxcvii
+1999 - mcmxcix
+2000 - mm
+2008 - mmviii
+2500 - mmd
+3000 - mmm
+4000 - mV
+4999 - mVcmxcix
+5000 - V
+6666 - Vmdclxvi
+10000 - X
+50000 - L
+100000 - C
+500000 - D
+1000000 - M
+2147483647 - MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMCDLXXXmmmdcxlvii
```
## ALGOL W
```algolw
BEGIN
PROCEDURE ROMAN (INTEGER VALUE NUMBER; STRING(15) RESULT CHARACTERS; INTEGER RESULT LENGTH);
COMMENT
Returns the Roman number of an integer between 1 and 3999.
"MMMDCCCLXXXVIII" (15 characters long) is the longest Roman number under 4000;
BEGIN
INTEGER PLACE, POWER;
PROCEDURE APPEND (STRING(1) VALUE C);
BEGIN CHARACTERS(LENGTH|1) := C; LENGTH := LENGTH + 1 END;
PROCEDURE I; APPEND(CASE PLACE OF ("I","X","C","M"));
PROCEDURE V; APPEND(CASE PLACE OF ("V","L","D"));
PROCEDURE X; APPEND(CASE PLACE OF ("X","C","M"));
ASSERT (NUMBER >= 1) AND (NUMBER < 4000);
CHARACTERS := " ";
LENGTH := 0;
POWER := 1000;
PLACE := 4;
WHILE PLACE > 0 DO
BEGIN
CASE NUMBER DIV POWER + 1 OF BEGIN
BEGIN END;
BEGIN I END;
BEGIN I; I END;
BEGIN I; I; I END;
BEGIN I; V END;
BEGIN V END;
BEGIN V; I END;
BEGIN V; I; I END;
BEGIN V; I; I; I END;
BEGIN I; X END
END;
NUMBER := NUMBER REM POWER;
POWER := POWER DIV 10;
PLACE := PLACE - 1
END
END ROMAN;
INTEGER I;
STRING(15) S;
ROMAN(1, S, I); WRITE(S, I);
ROMAN(3999, S, I); WRITE(S, I);
ROMAN(3888, S, I); WRITE(S, I);
ROMAN(2009, S, I); WRITE(S, I);
ROMAN(405, S, I); WRITE(S, I);
END.
```
```txt
I 1
MMMCMXCIX 9
MMMDCCCLXXXVIII 15
MMIX 4
CDV 3
```
## AppleScript
(ES6 version)
(mapAccumL version)
```AppleScript
-- ROMAN INTEGER STRINGS ------------------------------------------------------
-- roman :: Int -> String
on roman(n)
set kvs to {["M", 1000], ["CM", 900], ["D", 500], ¬
["CD", 400], ["C", 100], ["XC", 90], ["L", 50], ["XL", 40], ¬
["X", 10], ["IX", 9], ["V", 5], ["IV", 4], ["I", 1]}
script stringAddedValueDeducted
on |λ|(balance, kv)
set {k, v} to kv
set {q, r} to quotRem(balance, v)
if q > 0 then
{r, concat(replicate(q, k))}
else
{r, ""}
end if
end |λ|
end script
concat(snd(mapAccumL(stringAddedValueDeducted, n, kvs)))
end roman
-- TEST -----------------------------------------------------------------------
on run
map(roman, [2016, 1990, 2008, 2000, 1666])
--> {"MMXVI", "MCMXC", "MMVIII", "MM", "MDCLXVI"}
end run
-- GENERIC LIBRARY FUNCTIONS --------------------------------------------------
-- concat :: [[a]] -> [a] | [String] -> String
on concat(xs)
script append
on |λ|(a, b)
a & b
end |λ|
end script
if length of xs > 0 and class of (item 1 of xs) is string then
set unit to ""
else
set unit to {}
end if
foldl(append, unit, xs)
end concat
-- foldl :: (a -> b -> a) -> a -> [b] -> a
on foldl(f, startValue, xs)
tell mReturn(f)
set v to startValue
set lng to length of xs
repeat with i from 1 to lng
set v to |λ|(v, item i of xs, i, xs)
end repeat
return v
end tell
end foldl
-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
tell mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, i, xs)
end repeat
return lst
end tell
end map
-- 'The mapAccumL function behaves like a combination of map and foldl;
-- it applies a function to each element of a list, passing an
-- accumulating parameter from left to right, and returning a final
-- value of this accumulator together with the new list.' (see Hoogle)
-- mapAccumL :: (acc -> x -> (acc, y)) -> acc -> [x] -> (acc, [y])
on mapAccumL(f, acc, xs)
script
on |λ|(a, x)
tell mReturn(f) to set pair to |λ|(item 1 of a, x)
[item 1 of pair, (item 2 of a) & {item 2 of pair}]
end |λ|
end script
foldl(result, [acc, {}], xs)
end mapAccumL
-- Lift 2nd class handler function into 1st class script wrapper
-- mReturn :: Handler -> Script
on mReturn(f)
if class of f is script then
f
else
script
property |λ| : f
end script
end if
end mReturn
-- quotRem :: Integral a => a -> a -> (a, a)
on quotRem(m, n)
{m div n, m mod n}
end quotRem
-- Egyptian multiplication - progressively doubling a list, appending
-- stages of doubling to an accumulator where needed for binary
-- assembly of a target length
-- replicate :: Int -> a -> [a]
on replicate(n, a)
set out to {}
if n < 1 then return out
set dbl to {a}
repeat while (n > 1)
if (n mod 2) > 0 then set out to out & dbl
set n to (n div 2)
set dbl to (dbl & dbl)
end repeat
return out & dbl
end replicate
-- snd :: (a, b) -> b
on snd(xs)
if class of xs is list and length of xs = 2 then
item 2 of xs
else
missing value
end if
end snd
```
```txt
{"MMXVI", "MCMXC", "MMVIII", "MM", "MDCLXVI"}
```
## AutoHotkey
```AutoHotkey
MsgBox % stor(444)
stor(value)
{
romans = M,CM,D,CD,C,XC,L,XL,X,IX,V,IV,I
M := 1000
CM := 900
D := 500
CD := 400
C := 100
XC := 90
L := 50
XL := 40
X := 10
IX := 9
V := 5
IV := 4
I := 1
Loop, Parse, romans, `,
{
While, value >= %A_LoopField%
{
result .= A_LoopField
value := value - (%A_LoopField%)
}
}
Return result . "O"
}
```
## Autolisp
```Autolisp
(defun c:roman() (romanNumber (getint "\n Enter number > "))
(defun romanNumber (n / uni dec hun tho nstr strlist nlist rom)
(if (and (> n 0) (<= n 3999))
(progn
(setq
UNI (list "" "I" "II" "III" "IV" "V" "VI" "VII" "VIII" "IX")
DEC (list "" "X" "XX" "XXX" "XL" "L" "LX" "LXX" "LXXX" "XC")
HUN (list "" "C" "CC" "CCC" "CD" "D" "DC" "DCC" "DCCC" "CM")
THO (list "" "M" "MM" "MMM")
nstr (itoa n)
)
(while (> (strlen nstr) 0) (setq strlist (append strlist (list (substr nstr 1 1))) nstr (substr nstr 2 (strlen nstr))))
(setq nlist (mapcar 'atoi strlist))
(cond
((> n 999)(setq rom(strcat(nth (car nlist) THO)(nth (cadr nlist) HUN)(nth (caddr nlist) DEC) (nth (last nlist)UNI ))))
((and (> n 99)(<= n 999))(setq rom(strcat (nth (car nlist) HUN)(nth (cadr nlist) DEC) (nth (last nlist)UNI ))))
((and (> n 9)(<= n 99))(setq rom(strcat (nth (car nlist) DEC) (nth (last nlist)UNI ))))
((<= n 9)(setq rom(nth (last nlist)UNI)))
)
)
(princ "\nNumber out of range!")
)
rom
)
```
```txt
1577 "MDLXXVII"
3999 "MMMCMXCIX"
888 "DCCCLXXXVIII"
159 "CLIX"
```
## AWK
```AWK
# syntax: GAWK -f ROMAN_NUMERALS_ENCODE.AWK
BEGIN {
leng = split("1990 2008 1666",arr," ")
for (i=1; i<=leng; i++) {
n = arr[i]
printf("%s = %s\n",n,dec2roman(n))
}
exit(0)
}
function dec2roman(number, v,w,x,y,roman1,roman10,roman100,roman1000) {
number = int(number) # force to integer
if (number < 1 || number > 3999) { # number is too small | big
return
}
split("I II III IV V VI VII VIII IX",roman1," ") # 1 2 ... 9
split("X XX XXX XL L LX LXX LXXX XC",roman10," ") # 10 20 ... 90
split("C CC CCC CD D DC DCC DCCC CM",roman100," ") # 100 200 ... 900
split("M MM MMM",roman1000," ") # 1000 2000 3000
v = (number - (number % 1000)) / 1000
number = number % 1000
w = (number - (number % 100)) / 100
number = number % 100
x = (number - (number % 10)) / 10
y = number % 10
return(roman1000[v] roman100[w] roman10[x] roman1[y])
}
```
```txt
1990 = MCMXC
2008 = MMVIII
1666 = MDCLXVI
```
## BASIC
```freebasic
DIM SHARED arabic(0 TO 12) AS Integer => {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 }
DIM SHARED roman(0 TO 12) AS String*2 => {"M", "CM", "D","CD", "C","XC","L","XL","X","IX","V","IV","I"}
FUNCTION toRoman(value AS Integer) AS String
DIM i AS Integer
DIM result AS String
FOR i = 0 TO 12
DO WHILE value >= arabic(i)
result = result + roman(i)
value = value - arabic(i)
LOOP
NEXT i
toRoman = result
END FUNCTION
'Testing
PRINT "2009 = "; toRoman(2009)
PRINT "1666 = "; toRoman(1666)
PRINT "3888 = "; toRoman(3888)
```
```txt
2009 = MMIX
1666 = MDCLXVI
3888 = MMMDCCCLXXXVIII
```
==={{header|IS-BASIC}}===
100 PROGRAM "Roman.bas"
110 DO
120 PRINT :INPUT PROMPT "Enter an arabic number: ":N
130 IF N<1 THEN EXIT DO
140 PRINT TOROMAN$(N)
150 LOOP
160 DEF TOROMAN$(X)
170 IF X>3999 THEN
180 LET TOROMAN$="Too big."
190 EXIT DEF
200 END IF
210 RESTORE
220 LET SUM$=""
230 FOR I=1 TO 13
240 READ ARABIC,ROMAN$
250 DO WHILE X>=ARABIC
260 LET SUM$=SUM$&ROMAN$
270 LET X=X-ARABIC
280 LOOP
290 NEXT
300 LET TOROMAN$=SUM$
310 END DEF
320 DATA 1000,"M",900,"CM",500,"D",400,"CD",100,"C",90,"XC"
330 DATA 50,"L",40,"XL",10,"X",9,"IX",5,"V",4,"IV",1,"I"
```
=== {{header|ZX Spectrum Basic}} ===
```zxbasic
10 DATA 1000,"M",900,"CM"
20 DATA 500,"D",400,"CD"
30 DATA 100,"C",90,"XC"
40 DATA 50,"L",40,"XL"
50 DATA 10,"X",9,"IX"
60 DATA 5,"V",4,"IV",1,"I"
70 INPUT "Enter an arabic number: ";V
80 LET VALUE=V
90 LET V$=""
100 FOR I=0 TO 12
110 READ A,R$
120 IF V= arabic[i]
convert$ += roman$[i]
value = value - arabic[i]
end while
next i
end function
```
```txt
1666 = MDCLXVI
2008 = MMVIII
1001 = MI
1999 = MCMXCIX
```
## BBC BASIC
```bbcbasic
PRINT ;1999, FNroman(1999)
PRINT ;2012, FNroman(2012)
PRINT ;1666, FNroman(1666)
PRINT ;3888, FNroman(3888)
END
DEF FNroman(n%)
LOCAL i%, r$, arabic%(), roman$()
DIM arabic%(12), roman$(12)
arabic%() = 1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900,1000
roman$() = "I","IV", "V","IX", "X","XL", "L","XC", "C","CD", "D","CM", "M"
FOR i% = 12 TO 0 STEP -1
WHILE n% >= arabic%(i%)
r$ += roman$(i%)
n% -= arabic%(i%)
ENDWHILE
NEXT
= r$
```
```txt
1999 MCMXCIX
2012 MMXII
1666 MDCLXVI
3888 MMMDCCCLXXXVIII
```
## Befunge
Reads the number to convert from standard input. No range validation is performed.
```befunge
&>0\0>00p:#v_$ >:#,_ $ @
4-v >5+#:/#<\55+%:5/\5%:
vv_$9+00g+5g\00g8+>5g\00
g>\20p>:10p00g \#v _20gv
> 2+ v^-1g01\g5+8<^ +9 _
IVXLCDM
```
```txt
1666
MDCLXVI
```
## Bracmat
```bracmat
( ( encode
= indian roman cifr tenfoldroman letter tenfold
. !arg:#?indian
& :?roman
& whl
' ( @(!indian:#%?cifr ?indian)
& :?tenfoldroman
& whl
' ( !roman:%?letter ?roman
& !tenfoldroman
( (I.X)
(V.L)
(X.C)
(L.D)
(C.M)
: ? (!letter.?tenfold) ?
& !tenfold
| "*"
)
: ?tenfoldroman
)
& !tenfoldroman:?roman
& ( !cifr:9&!roman I X:?roman
| !cifr:~<4
& !roman
(!cifr:4&I|)
V
: ?roman
& !cifr+-5:?cifr
& ~
| whl
' ( !cifr+-1:~<0:?cifr
& !roman I:?roman
)
)
)
& ( !roman:? "*" ?&~`
| str$!roman
)
)
& 1990 2008 1666 3888 3999 4000:?NS
& whl
' ( !NS:%?N ?NS
& out
$ ( encode$!N:?K&!N !K
| str$("Can't convert " !N " to Roman numeral")
)
)
);
```
```txt
1990 MCMXC
2008 MMVIII
1666 MDCLXVI
3888 MMMDCCCLXXXVIII
3999 MMMCMXCIX
Can't convert 4000 to Roman numeral
```
## C
```cpp
#include
#include
/*
* Writes the Roman numeral representing n into the buffer s.
* Handles up to n = 3999.
* Since C doesn't have exceptions, n = 0 causes the whole program to exit
* unsuccessfully.
* s should be have room for at least 16 characters, including the trailing
* null.
*/
void roman(char *s, unsigned int n)
{
if (n == 0)
{
fputs("Roman numeral for zero requested.", stderr);
exit(EXIT_FAILURE);
}
#define digit(loop, num, c) \
loop (n >= num) \
{*(s++) = c; \
n -= num;}
#define digits(loop, num, c1, c2) \
loop (n >= num) \
{*(s++) = c1; \
*(s++) = c2; \
n -= num;}
digit ( while, 1000, 'M' )
digits ( if, 900, 'C', 'M' )
digit ( if, 500, 'D' )
digits ( if, 400, 'C', 'D' )
digit ( while, 100, 'C' )
digits ( if, 90, 'X', 'C' )
digit ( if, 50, 'L' )
digits ( if, 40, 'X', 'L' )
digit ( while, 10, 'X' )
digits ( if, 9, 'I', 'X' )
digit ( if, 5, 'V' )
digits ( if, 4, 'I', 'V' )
digit ( while, 1, 'I' )
#undef digit
#undef digits
*s = 0;}
int main(void)
{
char buffer[16];
unsigned int i;
for (i = 1 ; i < 4000 ; ++i)
{
roman(buffer, i);
printf("%4u: %s\n", i, buffer);
}
return EXIT_SUCCESS;
}
```
An alternative version which builds the string backwards.
```c
char *ToRoman(int num, char *buf, int buflen)
{
static const char romanDgts[] = "ivxlcdmVXLCDM_";
char *roman = buf + buflen;
int rdix, r, v;
*--roman = '\0'; /* null terminate return string */
if (num >= 4000000) {
printf("Number Too Big.\n");
return NULL;
}
for (rdix = 0; rdix < strlen(romanDgts); rdix += 2) {
if (num == 0) break;
v = (num % 10) / 5;
r = num % 5;
num = num / 10;
if (r == 4) {
if (roman < buf+2) {
printf("Buffer too small.");
return NULL;
}
*--roman = romanDgts[rdix+1+v];
*--roman = romanDgts[rdix];
}
else {
if (roman < buf+r+v) {
printf("Buffer too small.");
return NULL;
}
while(r-- > 0) {
*--roman = romanDgts[rdix];
}
if (v==1) {
*--roman = romanDgts[rdix+1];
}
}
}
return roman;
}
```
Most straightforward (nothing elegant about it,
but it's simple, and can calculate output length)
```c
#include
int to_roman(char *out, int n)
{
int len = 0;
if (n <= 0) return 0; /* error indication */
# define RPUT(c) if (out) out[len] = c; len++
while(n>= 1000) { n -= 1000;RPUT('M'); };
if (n >= 900) { n -= 900; RPUT('C'); RPUT('M'); };
if (n >= 500) { n -= 500; RPUT('D'); };
if (n >= 400) { n -= 400; RPUT('C'); RPUT('D'); };
while (n >= 100){ n -= 100; RPUT('C'); };
if (n >= 90) { n -= 90; RPUT('X'); RPUT('C'); };
if (n >= 50) { n -= 50; RPUT('L'); };
if (n >= 40) { n -= 40; RPUT('X'); RPUT('L'); };
while (n >= 10) { n -= 10; RPUT('X'); };
if (n >= 9) { n -= 9; RPUT('I'); RPUT('X'); };
if (n >= 5) { n -= 5; RPUT('V'); };
if (n >= 4) { n -= 4; RPUT('I'); RPUT('V'); };
while (n) { n--; RPUT('I'); };
RPUT('\0');
# undef RPUT
return len;
}
int main()
{
char buf[16];
int d = to_roman(buf, 1666);
printf("roman for 1666 is %d bytes: %s\n", d, buf);
d = 68999123;
printf("%d would have required %d bytes\n", d, to_roman(0, d));
return 0;
}
```
```txt
roman for 1666 is 8 bytes: MDCLXVI
68999123 would have required 69006 bytes
```
## C#
```c#
using System;
class Program
{
static uint[] nums = { 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 };
static string[] rum = { "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I" };
static string ToRoman(uint number)
{
string value = "";
for (int i = 0; i < nums.Length && number != 0; i++)
{
while (number >= nums[i])
{
number -= nums[i];
value += rum[i];
}
}
return value;
}
static void Main()
{
for (uint number = 1; number <= 1 << 10; number *= 2)
{
Console.WriteLine("{0} = {1}", number, ToRoman(number));
}
}
}
```
One-liner Mono REPL
```c#
Func toRoman = (number) =>
new Dictionary
{
{1000, "M"},
{900, "CM"},
{500, "D"},
{400, "CD"},
{100, "C"},
{90, "XC"},
{50, "L"},
{40, "XL"},
{10, "X"},
{9, "IX"},
{5, "V"},
{4, "IV"},
{1, "I"}
}.Aggregate(new string('I', number), (m, _) => m.Replace(new string('I', _.Key), _.Value));
```
```txt
1 = I
2 = II
4 = IV
8 = VIII
16 = XVI
32 = XXXII
64 = LXIV
128 = CXXVIII
256 = CCLVI
512 = DXII
1024 = MXXIV
```
## C++
### C++ 98
```cpp
#include
#include
std::string to_roman(int value)
{
struct romandata_t { int value; char const* numeral; };
static romandata_t const romandata[] =
{ 1000, "M",
900, "CM",
500, "D",
400, "CD",
100, "C",
90, "XC",
50, "L",
40, "XL",
10, "X",
9, "IX",
5, "V",
4, "IV",
1, "I",
0, NULL }; // end marker
std::string result;
for (romandata_t const* current = romandata; current->value > 0; ++current)
{
while (value >= current->value)
{
result += current->numeral;
value -= current->value;
}
}
return result;
}
int main()
{
for (int i = 1; i <= 4000; ++i)
{
std::cout << to_roman(i) << std::endl;
}
}
```
### C++ 11
```cpp
#include
#include
std::string to_roman(int x) {
auto roman_digit = [&](char one, char five, char ten, int x) {
if (x <= 3)
return std::string().assign(x, one);
if (x <= 5)
return std::string().assign(5 - x, one) + five;
if (x <= 8)
return five + std::string().assign(x - 5, one);
return std::string().assign(10 - x, one) + ten;
};
if (x <= 0)
return "Negative or zero!";
if (x >= 1000)
return "M" + to_roman(x - 1000);
if (x >= 100)
return roman_digit('C', 'D', 'M', x / 100) + to_roman(x % 100);
if (x >= 10)
return roman_digit('X', 'L', 'C', x / 10) + to_roman(x % 10);
return roman_digit('I', 'V', 'X', x);
}
int main(){
for (int i = 1; i < 2018; i+= 1)
std::cout << i << " --> " << to_roman(i) << std::endl;
}
```
## Ceylon
```ceylon
shared void run() {
class Numeral(shared Character char, shared Integer int) {}
value tiers = [
[Numeral('I', 1), Numeral('V', 5), Numeral('X', 10)],
[Numeral('X', 10), Numeral('L', 50), Numeral('C', 100)],
[Numeral('C', 100), Numeral('D', 500), Numeral('M', 1k)]
];
String toRoman(Integer hindu, Integer tierIndex = 2) {
assert (exists tier = tiers[tierIndex]);
" Finds if it's a two character numeral like iv, ix, xl, xc, cd and cm."
function findTwoCharacterNumeral() =>
if (exists bigNum = tier.rest.find((numeral) => numeral.int - tier.first.int <= hindu < numeral.int))
then [tier.first, bigNum]
else null;
if (hindu <= 0) {
// if it's zero then we are done!
return "";
}
else if (exists [smallNum, bigNum] = findTwoCharacterNumeral()) {
value twoCharSymbol = "``smallNum.char````bigNum.char``";
value twoCharValue = bigNum.int - smallNum.int;
return "``twoCharSymbol````toRoman(hindu - twoCharValue, tierIndex)``";
}
else if (exists num = tier.reversed.find((Numeral elem) => hindu >= elem.int)) {
return "``num.char````toRoman(hindu - num.int, tierIndex)``";
}
else {
// nothing was found so move to the next smaller tier!
return toRoman(hindu, tierIndex - 1);
}
}
assert (toRoman(1) == "I");
assert (toRoman(2) == "II");
assert (toRoman(4) == "IV");
assert (toRoman(1666) == "MDCLXVI");
assert (toRoman(1990) == "MCMXC");
assert (toRoman(2008) == "MMVIII");
}
```
## Clojure
The easiest way is to use the built-in cl-format function
```Clojure
(def arabic->roman
(partial clojure.pprint/cl-format nil "~@R"))
(arabic->roman 147)
;"CXXIII"
(arabic->roman 99)
;"XCIX"
```
Alternatively:
```Clojure
(def roman-map
(sorted-map
1 "I", 4 "IV", 5 "V", 9 "IX",
10 "X", 40 "XL", 50 "L", 90 "XC",
100 "C", 400 "CD", 500 "D", 900 "CM"
1000 "M"))
(defn int->roman [n]
{:pre (integer? n)}
(loop [res (StringBuilder.), n n]
(if-let [v (roman-map n)]
(str (.append res v))
(let [[k v] (->> roman-map keys (filter #(> n %)) last (find roman-map))]
(recur (.append res v) (- n k))))))
(int->roman 1999)
; "MCMXCIX"
```
An alternate implementation:
```Clojure
(defn a2r [a]
(let [rv '(1000 500 100 50 10 5 1)
rm (zipmap rv "MDCLXVI")
dv (->> rv (take-nth 2) next #(interleave % %))]
(loop [a a rv rv dv dv r nil]
(if (<= a 0)
r
(let [v (first rv)
d (or (first dv) 0)
l (- v d)]
(cond
(= a v) (str r (rm v))
(= a l) (str r (rm d) (rm v))
(and (> a v) (> a l)) (recur (- a v) rv dv (str r (rm v)))
(and (< a v) (< a l)) (recur a (rest rv) (rest dv) r)
:else (recur (- a l) (rest rv) (rest dv) (str r (rm d) (rm v)))))))))
```
Usage:
```Clojure
(a2r 1666)
"MDCLXVI"
(map a2r [1000 1 389 45])
("M" "I" "CCCLXXXIX" "XLV")
```
An alternate implementation:
```Clojure
(def roman-map
(sorted-map-by >
1 "I", 4 "IV", 5 "V", 9 "IX",
10 "X", 40 "XL", 50 "L", 90 "XC",
100 "C", 400 "CD", 500 "D", 900 "CM"
1000 "M"))
(defn a2r
([r]
(reduce str (a2r r (keys roman-map))))
([r n]
(when-not (empty? n)
(let [e (first n)
v (- r e)
roman (roman-map e)]
(cond
(< v 0) (a2r r (rest n))
(= v 0) (cons roman [])
(>= v e) (cons roman (a2r v n))
(< v e) (cons roman (a2r v (rest n))))))))
```
Usage:
```Clojure
(a2r 1666)
"MDCLXVI"
(map a2r [1000 1 389 45])
("M" "I" "CCCLXXXIX" "XLV")
```
## COBOL
```COBOL
IDENTIFICATION DIVISION.
PROGRAM-ID. TOROMAN.
DATA DIVISION.
working-storage section.
01 ws-number pic 9(4) value 0.
01 ws-save-number pic 9(4).
01 ws-tbl-def.
03 filler pic x(7) value '1000M '.
03 filler pic x(7) value '0900CM '.
03 filler pic x(7) value '0500D '.
03 filler pic x(7) value '0400CD '.
03 filler pic x(7) value '0100C '.
03 filler pic x(7) value '0090XC '.
03 filler pic x(7) value '0050L '.
03 filler pic x(7) value '0040XL '.
03 filler pic x(7) value '0010X '.
03 filler pic x(7) value '0009IX '.
03 filler pic x(7) value '0005V '.
03 filler pic x(7) value '0004IV '.
03 filler pic x(7) value '0001I '.
01 filler redefines ws-tbl-def.
03 filler occurs 13 times indexed by rx.
05 ws-tbl-divisor pic 9(4).
05 ws-tbl-roman-ch pic x(1) occurs 3 times indexed by cx.
01 ocx pic 99.
01 ws-roman.
03 ws-roman-ch pic x(1) occurs 16 times.
PROCEDURE DIVISION.
accept ws-number
perform
until ws-number = 0
move ws-number to ws-save-number
if ws-number > 0 and ws-number < 4000
initialize ws-roman
move 0 to ocx
perform varying rx from 1 by +1
until ws-number = 0
perform until ws-number < ws-tbl-divisor (rx)
perform varying cx from 1 by +1
until ws-tbl-roman-ch (rx, cx) = spaces
compute ocx = ocx + 1
move ws-tbl-roman-ch (rx, cx) to ws-roman-ch (ocx)
end-perform
compute ws-number = ws-number - ws-tbl-divisor (rx)
end-perform
end-perform
display 'inp=' ws-save-number ' roman=' ws-roman
else
display 'inp=' ws-save-number ' invalid'
end-if
accept ws-number
end-perform
.
```
{{out}} (input was supplied via STDIN)
```txt
inp=0111 roman=CXI
inp=2234 roman=MMCCXXXIV
inp=0501 roman=DI
inp=0010 roman=X
inp=0040 roman=XL
inp=0050 roman=L
inp=0066 roman=LXVI
inp=0666 roman=DCLXVI
inp=5666 invalid
inp=3333 roman=MMMCCCXXXIII
inp=3888 roman=MMMDCCCLXXXVIII
inp=3999 roman=MMMCMXCIX
inp=3345 roman=MMMCCCXLV
```
## CoffeeScript
```coffeescript
decimal_to_roman = (n) ->
# This should work for any positive integer, although it
# gets a bit preposterous for large numbers.
if n >= 4000
thousands = decimal_to_roman n / 1000
ones = decimal_to_roman n % 1000
return "M(#{thousands})#{ones}"
s = ''
translate_each = (min, roman) ->
while n >= min
n -= min
s += roman
translate_each 1000, "M"
translate_each 900, "CM"
translate_each 500, "D"
translate_each 400, "CD"
translate_each 100, "C"
translate_each 90, "XC"
translate_each 50, "L"
translate_each 40, "XL"
translate_each 10, "X"
translate_each 9, "IX"
translate_each 5, "V"
translate_each 4, "IV"
translate_each 1, "I"
s
###################
tests =
IV: 4
XLII: 42
MCMXC: 1990
MMVIII: 2008
MDCLXVI: 1666
'M(IV)': 4000
'M(VI)IX': 6009
'M(M(CXXIII)CDLVI)DCCLXXXIX': 123456789
'M(MMMV)I': 3005001
for expected, decimal of tests
roman = decimal_to_roman(decimal)
if roman == expected
console.log "#{decimal} = #{roman}"
else
console.log "error for #{decimal}: #{roman} is wrong"
```
## Common Lisp
```lisp
(defun roman-numeral (n)
(format nil "~@R" n))
```
## D
```d
string toRoman(int n) pure nothrow
in {
assert(n < 5000);
} body {
static immutable weights = [1000, 900, 500, 400, 100, 90,
50, 40, 10, 9, 5, 4, 1];
static immutable symbols = ["M","CM","D","CD","C","XC","L",
"XL","X","IX","V","IV","I"];
string roman;
foreach (i, w; weights) {
while (n >= w) {
roman ~= symbols[i];
n -= w;
}
if (n == 0)
break;
}
return roman;
} unittest {
assert(toRoman(455) == "CDLV");
assert(toRoman(3456) == "MMMCDLVI");
assert(toRoman(2488) == "MMCDLXXXVIII");
}
void main() {}
```
## Delphi
```delphi
program RomanNumeralsEncode;
{$APPTYPE CONSOLE}
function IntegerToRoman(aValue: Integer): string;
var
i: Integer;
const
WEIGHTS: array[0..12] of Integer = (1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1);
SYMBOLS: array[0..12] of string = ('M', 'CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I');
begin
for i := Low(WEIGHTS) to High(WEIGHTS) do
begin
while aValue >= WEIGHTS[i] do
begin
Result := Result + SYMBOLS[i];
aValue := aValue - WEIGHTS[i];
end;
if aValue = 0 then
Break;
end;
end;
begin
Writeln(IntegerToRoman(1990)); // MCMXC
Writeln(IntegerToRoman(2008)); // MMVIII
Writeln(IntegerToRoman(1666)); // MDCLXVI
end.
```
## DWScript
```delphi
const weights = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];
const symbols = ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"];
function toRoman(n : Integer) : String;
var
i, w : Integer;
begin
for i := 0 to weights.High do begin
w := weights[i];
while n >= w do begin
Result += symbols[i];
n -= w;
end;
if n = 0 then Break;
end;
end;
PrintLn(toRoman(455));
PrintLn(toRoman(3456));
PrintLn(toRoman(2488));
```
## ECL
```ECL
RomanEncode(UNSIGNED Int) := FUNCTION
SetWeights := [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];
SetSymbols := ['M', 'CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I'];
ProcessRec := RECORD
UNSIGNED val;
STRING Roman;
END;
dsWeights := DATASET(13,TRANSFORM(ProcessRec,SELF.val := Int, SELF := []));
SymbolStr(i,n,STRING s) := CHOOSE(n+1,'',SetSymbols[i],SetSymbols[i]+SetSymbols[i],SetSymbols[i]+SetSymbols[i]+SetSymbols[i],s);
RECORDOF(dsWeights) XF(dsWeights L, dsWeights R, INTEGER C) := TRANSFORM
ThisVal := IF(C=1,R.Val,L.Val);
IsDone := ThisVal = 0;
SELF.Roman := IF(IsDone,L.Roman,L.Roman + SymbolStr(C,ThisVal DIV SetWeights[C],L.Roman));
SELF.val := IF(IsDone,0,ThisVal - ((ThisVal DIV SetWeights[C])*SetWeights[C]));
END;
i := ITERATE(dsWeights,XF(LEFT,RIGHT,COUNTER));
RETURN i[13].Roman;
END;
RomanEncode(1954); //MCMLIV
RomanEncode(1990 ); //MCMXC
RomanEncode(2008 ); //MMVIII
RomanEncode(1666); //MDCLXVI
```
## Eiffel
```Eiffel
class
APPLICATION
create
make
feature {NONE} -- Initialization
make
local
numbers: ARRAY [INTEGER]
do
numbers := <<1990, 2008, 1666, 3159, 1977, 2010>>
-- "MCMXC", "MMVIII", "MDCLXVI", "MMMCLIX", "MCMLXXVII", "MMX"
across numbers as n loop
print (n.item.out + " in decimal Arabic numerals is " +
decimal_to_roman (n.item) + " in Roman numerals.%N")
end
end
feature -- Roman numerals
decimal_to_roman (a_int: INTEGER): STRING
-- Representation of integer `a_int' as Roman numeral
require
a_int > 0
local
dnums: ARRAY[INTEGER]
rnums: ARRAY[STRING]
dnum: INTEGER
rnum: STRING
i: INTEGER
do
dnums := <<1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1>>
rnums := <<"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I">>
dnum := a_int
rnum := ""
from
i := 1
until
i > dnums.count or dnum <= 0
loop
from
until
dnum < dnums[i]
loop
dnum := dnum - dnums[i]
rnum := rnum + rnums[i]
end
i := i + 1
end
Result := rnum
end
end
```
## Ela
```ela
open number string math
digit x y z k =
[[x],[x,x],[x,x,x],[x,y],[y],[y,x],[y,x,x],[y,x,x,x],[x,z]] :
(toInt k - 1)
toRoman 0 = ""
toRoman x | x < 0 = fail "Negative roman numeral"
| x >= 1000 = 'M' :: toRoman (x - 1000)
| x >= 100 = let (q,r) = x `divrem` 100 in
digit 'C' 'D' 'M' q ++ toRoman r
| x >= 10 = let (q,r) = x `divrem` 10 in
digit 'X' 'L' 'C' q ++ toRoman r
| else = digit 'I' 'V' 'X' x
map (join "" << toRoman) [1999,25,944]
```
```txt
["MCMXCIX","XXV","CMXLIV"]
```
## Elena
ELENA 4.x :
```elena
import system'collections;
import system'routines;
import extensions;
import extensions'text;
static RomanDictionary = new Dictionary()
.setAt(1000, "M")
.setAt(900, "CM")
.setAt(500, "D")
.setAt(400, "CD")
.setAt(100, "C")
.setAt(90, "XC")
.setAt(50, "L")
.setAt(40, "XL")
.setAt(10, "X")
.setAt(9, "IX")
.setAt(5, "V")
.setAt(4, "IV")
.setAt(1, "I");
extension op
{
toRoman()
= RomanDictionary.accumulate(new StringWriter("I", self), (m,kv => m.replace(new StringWriter("I",kv.Key), kv.Value)));
}
public program()
{
console.printLine("1990 : ", 1990.toRoman());
console.printLine("2008 : ", 2008.toRoman());
console.printLine("1666 : ", 1666.toRoman())
}
```
```txt
1990 : MCMXC
2008 : MMVIII
1666 : MDCLXVI
```
## Elixir
```elixir
defmodule Roman_numeral do
def encode(0), do: ''
def encode(x) when x >= 1000, do: [?M | encode(x - 1000)]
def encode(x) when x >= 100, do: digit(div(x,100), ?C, ?D, ?M) ++ encode(rem(x,100))
def encode(x) when x >= 10, do: digit(div(x,10), ?X, ?L, ?C) ++ encode(rem(x,10))
def encode(x) when x >= 1, do: digit(x, ?I, ?V, ?X)
defp digit(1, x, _, _), do: [x]
defp digit(2, x, _, _), do: [x, x]
defp digit(3, x, _, _), do: [x, x, x]
defp digit(4, x, y, _), do: [x, y]
defp digit(5, _, y, _), do: [y]
defp digit(6, x, y, _), do: [y, x]
defp digit(7, x, y, _), do: [y, x, x]
defp digit(8, x, y, _), do: [y, x, x, x]
defp digit(9, x, _, z), do: [x, z]
end
```
'''Another:'''
```elixir
defmodule Roman_numeral do
@symbols [ {1000, 'M'}, {900, 'CM'}, {500, 'D'}, {400, 'CD'}, {100, 'C'}, {90, 'XC'},
{50, 'L'}, {40, 'XL'}, {10, 'X'}, {9, 'IX'}, {5, 'V'}, {4, 'IV'}, {1, 'I'} ]
def encode(num) do
{roman,_} = Enum.reduce(@symbols, {[], num}, fn {divisor, letter}, {memo, n} ->
{memo ++ List.duplicate(letter, div(n, divisor)), rem(n, divisor)}
end)
Enum.join(roman)
end
end
```
'''Test:'''
```elixir
Enum.each([1990, 2008, 1666], fn n ->
IO.puts "#{n}: #{Roman_numeral.encode(n)}"
end)
```
```txt
1990: MCMXC
2008: MMVIII
1666: MDCLXVI
```
## Emacs Lisp
```lisp
(defun ar2ro (AN)
"translate from arabic number AN to roman number,
ar2ro(1666) returns (M D C L X V I)"
(cond
((>= AN 1000) (cons 'M (ar2ro (- AN 1000))))
((>= AN 900) (cons 'C (cons 'M (ar2ro (- AN 900)))))
((>= AN 500) (cons 'D (ar2ro (- AN 500))))
((>= AN 400) (cons 'C (cons 'D (ar2ro (- AN 400)))))
((>= AN 100) (cons 'C (ar2ro (- AN 100))))
((>= AN 90) (cons 'X (cons 'C (ar2ro (- AN 90)))))
((>= AN 50) (cons 'L (ar2ro (- AN 50))))
((>= AN 40) (cons 'X (cons 'L (ar2ro (- AN 40)))))
((>= AN 10) (cons 'X (ar2ro (- AN 10))))
((>= AN 5) (cons 'V (ar2ro (- AN 5))))
((>= AN 4) (cons 'I (cons 'V (ar2ro (- AN 4)))))
((>= AN 1) (cons 'I (ar2ro (- AN 1))))
((= AN 0) nil)))
```
## Erlang
```erlang
-module(roman).
-export([to_roman/1]).
to_roman(0) -> [];
to_roman(X) when X >= 1000 -> [$M | to_roman(X - 1000)];
to_roman(X) when X >= 100 ->
digit(X div 100, $C, $D, $M) ++ to_roman(X rem 100);
to_roman(X) when X >= 10 ->
digit(X div 10, $X, $L, $C) ++ to_roman(X rem 10);
to_roman(X) when X >= 1 -> digit(X, $I, $V, $X).
digit(1, X, _, _) -> [X];
digit(2, X, _, _) -> [X, X];
digit(3, X, _, _) -> [X, X, X];
digit(4, X, Y, _) -> [X, Y];
digit(5, _, Y, _) -> [Y];
digit(6, X, Y, _) -> [Y, X];
digit(7, X, Y, _) -> [Y, X, X];
digit(8, X, Y, _) -> [Y, X, X, X];
digit(9, X, _, Z) -> [X, Z].
```
sample:
```txt
1> c(roman).
{ok,roman}
2> roman:to_roman(1999).
"MCMXCIX"
3> roman:to_roman(25).
"XXV"
4> roman:to_roman(944).
"CMXLIV"
```
Alternative:
```erlang
-module( roman_numerals ).
-export( [encode_from_integer/1]).
-record( encode_acc, {n, romans=""} ).
encode_from_integer( N ) when N > 0 ->
#encode_acc{romans=Romans} = lists:foldl( fun encode_from_integer/2, #encode_acc{n=N}, map() ),
Romans.
encode_from_integer( _Map, #encode_acc{n=0}=Acc ) -> Acc;
encode_from_integer( {_Roman, Value}, #encode_acc{n=N}=Acc ) when N < Value -> Acc;
encode_from_integer( {Roman, Value}, #encode_acc{n=N, romans=Romans} ) ->
Times = N div Value,
New_roman = lists:flatten( lists:duplicate(Times, Roman) ),
#encode_acc{n=N - (Times * Value), romans=Romans ++ New_roman}.
map() -> [{"M",1000}, {"CM",900}, {"D",500}, {"CD",400}, {"C",100}, {"XC",90}, {"L",50}, {"XL",40}, {"X",10}, {"IX",9}, {"V",5}, {"IV",4}, {"I\
",1}].
```
```txt
36> roman_numerals:encode_from_integer( 1990 ).
"MCMXC"
37> roman_numerals:encode_from_integer( 2008 ).
"MMVIII"
38> roman_numerals:encode_from_integer( 1666 ).
"MDCLXVI"
```
## ERRE
```ERRE
PROGRAM ARAB2ROMAN
DIM ARABIC%[12],ROMAN$[12]
PROCEDURE TOROMAN(VALUE->ANS$)
LOCAL RESULT$
FOR I%=0 TO 12 DO
WHILE VALUE>=ARABIC%[I%] DO
RESULT$+=ROMAN$[I%]
VALUE-=ARABIC%[I%]
END WHILE
END FOR
ANS$=RESULT$
END PROCEDURE
BEGIN
!
!Testing
!
ARABIC%[]=(1000,900,500,400,100,90,50,40,10,9,5,4,1)
ROMAN$[]=("M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I")
TOROMAN(2009->ANS$) PRINT("2009 = ";ANS$)
TOROMAN(1666->ANS$) PRINT("1666 = ";ANS$)
TOROMAN(3888->ANS$) PRINT("3888 = ";ANS$)
END PROGRAM
```
## Euphoria
```Euphoria
constant arabic = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 }
constant roman = {"M", "CM", "D","CD", "C","XC","L","XL","X","IX","V","IV","I"}
function toRoman(integer val)
sequence result
result = ""
for i = 1 to 13 do
while val >= arabic[i] do
result &= roman[i]
val -= arabic[i]
end while
end for
return result
end function
printf(1,"%d = %s\n",{2009,toRoman(2009)})
printf(1,"%d = %s\n",{1666,toRoman(1666)})
printf(1,"%d = %s\n",{3888,toRoman(3888)})
```
```txt
2009 = MMIX
1666 = MDCLXVI
3888 = MMMDCCCLXXXVIII
```
## Excel
Excel can encode numbers in Roman forms in 5 successively concise forms.
These can be indicated from 0 to 4. Type in a cell:
```Excel
=ROMAN(2013,0)
```
It becomes:
MMXIII
```
=={{header|F_Sharp|F#}}==
```fsharp
let digit x y z = function
1 -> x
| 2 -> x + x
| 3 -> x + x + x
| 4 -> x + y
| 5 -> y
| 6 -> y + x
| 7 -> y + x + x
| 8 -> y + x + x + x
| 9 -> x + z
| _ -> failwith "invalid call to digit"
let rec to_roman acc = function
| x when x >= 1000 -> to_roman (acc + "M") (x - 1000)
| x when x >= 100 -> to_roman (acc + digit "C" "D" "M" (x / 100)) (x % 100)
| x when x >= 10 -> to_roman (acc + digit "X" "L" "C" (x / 10)) (x % 10)
| x when x > 0 -> acc + digit "I" "V" "X" x
| 0 -> acc
| _ -> failwith "invalid call to_roman (negative input)"
let roman n = to_roman "" n
[]
let main args =
[1990; 2008; 1666]
|> List.map (fun n -> roman n)
|> List.iter (printfn "%s")
0
```
```txt
MCMXC
MMVIII
MDCLXVI
```
## Factor
A roman numeral library ships with Factor.
```factor
USE: roman
( scratchpad ) 3333 >roman .
"mmmcccxxxiii"
```
Parts of the implementation:
```factor
CONSTANT: roman-digits
{ "m" "cm" "d" "cd" "c" "xc" "l" "xl" "x" "ix" "v" "iv" "i" }
CONSTANT: roman-values
{ 1000 900 500 400 100 90 50 40 10 9 5 4 1 }
ERROR: roman-range-error n ;
: roman-range-check ( n -- n )
dup 1 10000 between? [ roman-range-error ] unless ;
: >roman ( n -- str )
roman-range-check
roman-values roman-digits [
[ /mod swap ] dip concat
] 2map "" concat-as nip ;
```
## FALSE
```false
^$." "
[$999>][1000- "M"]#
$899> [ 900-"CM"]?
$499> [ 500- "D"]?
$399> [ 400-"CD"]?
[$ 99>][ 100- "C"]#
$ 89> [ 90-"XC"]?
$ 49> [ 50- "L"]?
$ 39> [ 40-"XL"]?
[$ 9>][ 10- "X"]#
$ 8> [ 9-"IX"]?
$ 4> [ 5- "V"]?
$ 3> [ 4-"IV"]?
[$ ][ 1- "I"]#%
```
## Fan
```Fan
**
** converts a number to its roman numeral representation
**
class RomanNumerals
{
private Str digit(Str x, Str y, Str z, Int i)
{
switch (i)
{
case 1: return x
case 2: return x+x
case 3: return x+x+x
case 4: return x+y
case 5: return y
case 6: return y+x
case 7: return y+x+x
case 8: return y+x+x+x
case 9: return x+z
}
return ""
}
Str toRoman(Int i)
{
if (i>=1000) { return "M" + toRoman(i-1000) }
if (i>=100) { return digit("C", "D", "M", i/100) + toRoman(i%100) }
if (i>=10) { return digit("X", "L", "C", i/10) + toRoman(i%10) }
if (i>=1) { return digit("I", "V", "X", i) }
return ""
}
Void main()
{
2000.times |i| { echo("$i = ${toRoman(i)}") }
}
}
```
## Forth
```forth
: vector create ( n -- ) 0 do , loop does> ( n -- ) swap cells + @ execute ;
\ these are ( numerals -- numerals )
: ,I dup c@ C, ; : ,V dup 1 + c@ C, ; : ,X dup 2 + c@ C, ;
\ these are ( numerals -- )
:noname ,I ,X drop ; :noname ,V ,I ,I ,I drop ; :noname ,V ,I ,I drop ;
:noname ,V ,I drop ; :noname ,V drop ; :noname ,I ,V drop ;
:noname ,I ,I ,I drop ; :noname ,I ,I drop ; :noname ,I drop ;
' drop ( 0 : no output ) 10 vector ,digit
: roman-rec ( numerals n -- ) 10 /mod dup if >r over 2 + r> recurse else drop then ,digit ;
: roman ( n -- c-addr u )
dup 0 4000 within 0= abort" EX LIMITO!"
HERE SWAP s" IVXLCDM" drop swap roman-rec HERE OVER - ;
1999 roman type \ MCMXCIX
25 roman type \ XXV
944 roman type \ CMXLIV
```
Alternative implementation
```forth
create romans 0 , 1 , 5 , 21 , 9 , 2 , 6 , 22 , 86 , 13 ,
does> swap cells + @ ;
: roman-digit ( a1 n1 a2 n2 -- a3)
drop >r romans
begin dup while tuck 4 mod 1- chars r@ + c@ over c! char+ swap 4 / repeat
r> drop drop
;
: (split) swap >r /mod r> swap ;
: >roman ( n1 a -- a n2)
tuck 1000 (split) s" M " roman-digit 100 (split) s" CDM" roman-digit
10 (split) s" XLC" roman-digit 1 (split) s" IVX" roman-digit nip over -
;
create (roman) 16 chars allot
1999 (roman) >roman type cr
```
## Fortran
```fortran
program roman_numerals
implicit none
write (*, '(a)') roman (2009)
write (*, '(a)') roman (1666)
write (*, '(a)') roman (3888)
contains
function roman (n) result (r)
implicit none
integer, intent (in) :: n
integer, parameter :: d_max = 13
integer :: d
integer :: m
integer :: m_div
character (32) :: r
integer, dimension (d_max), parameter :: d_dec = &
& (/1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1/)
character (32), dimension (d_max), parameter :: d_rom = &
& (/'M ', 'CM', 'D ', 'CD', 'C ', 'XC', 'L ', 'XL', 'X ', 'IX', 'V ', 'IV', 'I '/)
r = ''
m = n
do d = 1, d_max
m_div = m / d_dec (d)
r = trim (r) // repeat (trim (d_rom (d)), m_div)
m = m - d_dec (d) * m_div
end do
end function roman
end program roman_numerals
```
```txt
MMIX
MDCLXVI
MMMDCCCLXXXVIII
```
## FreeBASIC
```freebasic
' FB 1.05.0 Win64
Function romanEncode(n As Integer) As String
If n < 1 OrElse n > 3999 Then Return "" '' can only encode numbers in range 1 to 3999
Dim roman1(0 To 2) As String = {"MMM", "MM", "M"}
Dim roman2(0 To 8) As String = {"CM", "DCCC", "DCC", "DC", "D", "CD", "CCC", "CC", "C"}
Dim roman3(0 To 8) As String = {"XC", "LXXX", "LXX", "LX", "L", "XL", "XXX", "XX", "X"}
Dim roman4(0 To 8) As String = {"IX", "VIII", "VII", "VI", "V", "IV", "III", "II", "I"}
Dim As Integer thousands, hundreds, tens, units
thousands = n \ 1000
n Mod= 1000
hundreds = n \ 100
n Mod= 100
tens = n \ 10
units = n Mod 10
Dim roman As String = ""
If thousands > 0 Then roman += roman1(3 - thousands)
If hundreds > 0 Then roman += roman2(9 - hundreds)
If tens > 0 Then roman += roman3(9 - tens)
If units > 0 Then roman += roman4(9 - units)
Return roman
End Function
Dim a(2) As Integer = {1990, 2008, 1666}
For i As Integer = 0 To 2
Print a(i); " => "; romanEncode(a(i))
Next
Print
Print "Press any key to quit"
Sleep
```
```txt
1990 => MCMXC
2008 => MMVIII
1666 => MDCLXVI
```
## FutureBasic
```futurebasic
include "ConsoleWindow"
local fn DecimaltoRoman( decimal as short ) as Str15
dim as short arabic(12)
dim as Str15 roman(12)
dim as long i
dim as Str15 result : result = ""
arabic(0) = 1000 : arabic(1) = 900 : arabic(2) = 500 : arabic(3) = 400
arabic(4) = 100 : arabic(5) = 90 : arabic(6) = 50 : arabic(7) = 40
arabic(8) = 10 : arabic(9) = 9 : arabic(10) = 5 : arabic(11) = 4: arabic(12) = 1
roman(0) = "M" : roman(1) = "CM" : roman(2) = "D" : roman(3) = "CD"
roman(4) = "C" : roman(5) = "XC" : roman(6) = "L" : roman(7) = "XL"
roman(8) = "X" : roman(9) = "IX" : roman(10) = "V" : roman(11) = "IV" : roman(12) = "I"
for i = 0 to 12
while ( decimal >= arabic(i) )
result = result + roman(i)
decimal = decimal - arabic(i)
wend
next i
if result == "" then result = "Zepherium"
end fn = result
print "1990 = "; fn DecimaltoRoman( 1990 )
print "2008 = "; fn DecimaltoRoman( 2008 )
print "2016 = "; fn DecimaltoRoman( 2016 )
print "1666 = "; fn DecimaltoRoman( 1666 )
print "3888 = "; fn DecimaltoRoman( 3888 )
print "1914 = "; fn DecimaltoRoman( 1914 )
print "1000 = "; fn DecimaltoRoman( 1000 )
print " 513 = "; fn DecimaltoRoman( 513 )
print " 33 = "; fn DecimaltoRoman( 33 )
```
Output:
```txt
1990 = MCMXC
2008 = MMVIII
2016 = MMXVI
1666 = MDCLXVI
3888 = MMMDCCCLXXXVIII
1914 = MCMXIV
1000 = M
513 = DXIII
33 = XXXIII
```
## Go
For fluff, the unicode overbar is recognized as a factor of 1000, [http://en.wikipedia.org/wiki/Roman_numerals#Large_numbers as described in WP].
If you see boxes in the code below, those are supposed to be the Unicode combining overline (U+0305) and look like {{overline|IVXLCDM}}. Or, if you see overstruck combinations of letters, that's a different font rendering problem. (If you need roman numerals > 3999 reliably, it might best to stick to chiseling them in stone...)
```go
package main
import "fmt"
var (
m0 = []string{"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"}
m1 = []string{"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"}
m2 = []string{"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"}
m3 = []string{"", "M", "MM", "MMM", "I̅V̅",
"V̅", "V̅I̅", "V̅I̅I̅", "V̅I̅I̅I̅", "I̅X̅"}
m4 = []string{"", "X̅", "X̅X̅", "X̅X̅X̅", "X̅L̅",
"L̅", "L̅X̅", "L̅X̅X̅", "L̅X̅X̅X̅", "X̅C̅"}
m5 = []string{"", "C̅", "C̅C̅", "C̅C̅C̅", "C̅D̅",
"D̅", "D̅C̅", "D̅C̅C̅", "D̅C̅C̅C̅", "C̅M̅"}
m6 = []string{"", "M̅", "M̅M̅", "M̅M̅M̅"}
)
func formatRoman(n int) (string, bool) {
if n < 1 || n >= 4e6 {
return "", false
}
// this is efficient in Go. the seven operands are evaluated,
// then a single allocation is made of the exact size needed for the result.
return m6[n/1e6] + m5[n%1e6/1e5] + m4[n%1e5/1e4] + m3[n%1e4/1e3] +
m2[n%1e3/1e2] + m1[n%100/10] + m0[n%10],
true
}
func main() {
// show three numbers mentioned in task descriptions
for _, n := range []int{1990, 2008, 1666} {
r, ok := formatRoman(n)
if ok {
fmt.Println(n, "==", r)
} else {
fmt.Println(n, "not representable")
}
}
}
```
```txt
1990 == MCMXC
2008 == MMVIII
1666 == MDCLXVI
```
## Golo
```golo
#!/usr/bin/env golosh
----
This module takes a decimal integer and converts it to a Roman numeral.
----
module Romannumeralsencode
augment java.lang.Integer {
function digits = |this| {
var remaining = this
let digits = vector[]
while remaining > 0 {
digits: prepend(remaining % 10)
remaining = remaining / 10
}
return digits
}
----
123: digitsWithPowers() will return [[1, 2], [2, 1], [3, 0]]
----
function digitsWithPowers = |this| -> vector[
[ this: digits(): get(i), (this: digits(): size() - 1) - i ] for (var i = 0, i < this: digits(): size(), i = i + 1)
]
function encode = |this| {
require(this > 0, "the integer must be positive!")
let romanPattern = |digit, powerOf10| -> match {
when digit == 1 then i
when digit == 2 then i + i
when digit == 3 then i + i + i
when digit == 4 then i + v
when digit == 5 then v
when digit == 6 then v + i
when digit == 7 then v + i + i
when digit == 8 then v + i + i + i
when digit == 9 then i + x
otherwise ""
} with {
i, v, x = [
[ "I", "V", "X" ],
[ "X", "L", "C" ],
[ "C", "D", "M" ],
[ "M", "?", "?" ]
]: get(powerOf10)
}
return vector[ romanPattern(digit, power) foreach digit, power in this: digitsWithPowers() ]: join("")
}
}
function main = |args| {
println("1990 == MCMXC? " + (1990: encode() == "MCMXC"))
println("2008 == MMVIII? " + (2008: encode() == "MMVIII"))
println("1666 == MDCLXVI? " + (1666: encode() == "MDCLXVI"))
}
```
## Groovy
```groovy
symbols = [ 1:'I', 4:'IV', 5:'V', 9:'IX', 10:'X', 40:'XL', 50:'L', 90:'XC', 100:'C', 400:'CD', 500:'D', 900:'CM', 1000:'M' ]
def roman(arabic) {
def result = ""
symbols.keySet().sort().reverse().each {
while (arabic >= it) {
arabic-=it
result+=symbols[it]
}
}
return result
}
assert roman(1) == 'I'
assert roman(2) == 'II'
assert roman(4) == 'IV'
assert roman(8) == 'VIII'
assert roman(16) == 'XVI'
assert roman(32) == 'XXXII'
assert roman(25) == 'XXV'
assert roman(64) == 'LXIV'
assert roman(128) == 'CXXVIII'
assert roman(256) == 'CCLVI'
assert roman(512) == 'DXII'
assert roman(954) == 'CMLIV'
assert roman(1024) == 'MXXIV'
assert roman(1666) == 'MDCLXVI'
assert roman(1990) == 'MCMXC'
assert roman(2008) == 'MMVIII'
```
## Haskell
With an explicit decimal digit representation list:
```haskell
digit :: Char -> Char -> Char -> Integer -> String
digit x y z k =
[[x], [x, x], [x, x, x], [x, y], [y], [y, x], [y, x, x], [y, x, x, x], [x, z]] !!
(fromInteger k - 1)
toRoman :: Integer -> String
toRoman 0 = ""
toRoman x
| x < 0 = error "Negative roman numeral"
toRoman x
| x >= 1000 = 'M' : toRoman (x - 1000)
toRoman x
| x >= 100 = digit 'C' 'D' 'M' q ++ toRoman r
where
(q, r) = x `divMod` 100
toRoman x
| x >= 10 = digit 'X' 'L' 'C' q ++ toRoman r
where
(q, r) = x `divMod` 10
toRoman x = digit 'I' 'V' 'X' x
main :: IO ()
main = print $ toRoman <$> [1999, 25, 944]
```
```txt
["MCMXCIX","XXV","CMXLIV"]
```
or, defining '''roman''' in terms of mapAccumL
```haskell
import Data.List (mapAccumL)
roman :: [(Int, String)] -> Int -> String
roman vks n =
concat . snd $
mapAccumL
(\a (m, s) ->
let (q, r) = quotRem a m
in (r, [1 .. q] >> s))
n
vks
romanFromInt :: Int -> String
romanFromInt =
roman $
zip
[1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1]
["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"]
main :: IO ()
main = (putStrLn . unlines) (romanFromInt <$> [1666, 1990, 2008, 2016, 2018])
```
```txt
MDCLXVI
MCMXC
MMVIII
MMXVI
MMXVIII
```
With the Roman patterns abstracted, and in a simple logic programming idiom:
```haskell
module Main where
------------------------
-- ENCODER FUNCTION --
------------------------
romanDigits = "IVXLCDM"
-- Meaning and indices of the romanDigits sequence:
--
-- magnitude | 1 5 | index
-- -----------|-------|-------
-- 0 | I V | 0 1
-- 1 | X L | 2 3
-- 2 | C D | 4 5
-- 3 | M | 6
--
-- romanPatterns are index offsets into romanDigits,
-- from an index base of 2 * magnitude.
romanPattern 0 = [] -- empty string
romanPattern 1 = [0] -- I or X or C or M
romanPattern 2 = [0,0] -- II or XX...
romanPattern 3 = [0,0,0] -- III...
romanPattern 4 = [0,1] -- IV...
romanPattern 5 = [1] -- ...
romanPattern 6 = [1,0]
romanPattern 7 = [1,0,0]
romanPattern 8 = [1,0,0,0]
romanPattern 9 = [0,2]
encodeValue 0 _ = ""
encodeValue value magnitude = encodeValue rest (magnitude + 1) ++ digits
where
low = rem value 10 -- least significant digit (encoded now)
rest = div value 10 -- the other digits (to be encoded next)
indices = map addBase (romanPattern low)
addBase i = i + (2 * magnitude)
digits = map pickDigit indices
pickDigit i = romanDigits!!i
encode value = encodeValue value 0
------------------
-- TEST SUITE --
------------------
main = do
test "MCMXC" 1990
test "MMVIII" 2008
test "MDCLXVI" 1666
test expected value = putStrLn ((show value) ++ " = " ++ roman ++ remark)
where
roman = encode value
remark =
" (" ++
(if roman == expected then "PASS"
else ("FAIL, expected " ++ (show expected))) ++ ")"
```
```txt
1990 = MCMXC (PASS)
2008 = MMVIII (PASS)
1666 = MDCLXVI (PASS)
```
## HicEst
```hicest
CHARACTER Roman*20
CALL RomanNumeral(1990, Roman) ! MCMXC
CALL RomanNumeral(2008, Roman) ! MMVIII
CALL RomanNumeral(1666, Roman) ! MDCLXVI
END
SUBROUTINE RomanNumeral( arabic, roman)
CHARACTER roman
DIMENSION ddec(13)
DATA ddec/1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1/
roman = ' '
todo = arabic
DO d = 1, 13
DO rep = 1, todo / ddec(d)
roman = TRIM(roman) // TRIM(CHAR(d, 13, "M CM D CD C XC L XL X OX V IV I "))
todo = todo - ddec(d)
ENDDO
ENDDO
END
```
=={{header|Icon}} and {{header|Unicon}}==
```Icon
link numbers # commas, roman
procedure main(arglist)
every x := !arglist do
write(commas(x), " -> ",roman(x)|"*** can't convert to Roman numerals ***")
end
```
[http://www.cs.arizona.edu/icon/library/src/procs/numbers.icn numbers.icn provides roman] as seen below and is based upon a James Gimple SNOBOL4 function.
```Icon
procedure roman(n) #: convert integer to Roman numeral
local arabic, result
static equiv
initial equiv := ["","I","II","III","IV","V","VI","VII","VIII","IX"]
integer(n) > 0 | fail
result := ""
every arabic := !n do
result := map(result,"IVXLCDM","XLCDM**") || equiv[arabic + 1]
if find("*",result) then fail else return result
end
```
```txt
#roman.exe 3 4 8 49 2010 1666 3000 3999 4000
3 -> III
4 -> IV
8 -> VIII
49 -> XLIX
2,010 -> MMX
1,666 -> MDCLXVI
3,999 -> MMMCMXCIX
4,000 -> *** can't convert to Roman numerals ***
```
## Io
```Io
Roman := Object clone do (
nums := list(1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1)
rum := list("M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I")
numeral := method(number,
result := ""
for(i, 0, nums size,
if(number == 0, break)
while(number >= nums at(i),
number = number - nums at(i)
result = result .. rum at(i)
)
)
return result
)
)
Roman numeral(1666) println
```
## J
rfd obtains Roman numerals from decimals.
```j
R1000=. ;L:1 ,{ <@(<;._1);._2]0 :0
C CC CCC CD D DC DCC DCCC CM
X XX XXX XL L LX LXX LXXX XC
I II III IV V VI VII VIII IX
)
rfd=: ('M' $~ <.@%&1000) , R1000 {::~ 1000&|
```
Explanation: R1000's definition contains rows representing each of 10 different digits in the 100s, 10s and 1s column (the first entry in each row is blank -- each entry is preceded by a space). R1000 itself represents the first 1000 roman numerals (the cartesian product of these three rows of roman numeral "digits" which is constructed so that they are in numeric order. And the first entry -- zero -- is just blank). To convert a number to its roman numeral representation, we will separate the number into the integer part after dividing by 1000 (that's the number of 'M's we need) and the remainder after dividing by 1000 (which will be an index into R1000).
For example:
```j
rfd 1234
MCCXXXIV
rfd 567
DLXVII
rfd 89
LXXXIX
```
Derived from the [[j:Essays/Roman Numerals|J Wiki]]. Further examples of use will be found there.
## Java
The conversion function throws an IllegalArgumentException for non-positive numbers, since Java does not have unsigned primitives.
```java5
public class RN {
enum Numeral {
I(1), IV(4), V(5), IX(9), X(10), XL(40), L(50), XC(90), C(100), CD(400), D(500), CM(900), M(1000);
int weight;
Numeral(int weight) {
this.weight = weight;
}
};
public static String roman(long n) {
if( n <= 0) {
throw new IllegalArgumentException();
}
StringBuilder buf = new StringBuilder();
final Numeral[] values = Numeral.values();
for (int i = values.length - 1; i >= 0; i--) {
while (n >= values[i].weight) {
buf.append(values[i]);
n -= values[i].weight;
}
}
return buf.toString();
}
public static void test(long n) {
System.out.println(n + " = " + roman(n));
}
public static void main(String[] args) {
test(1999);
test(25);
test(944);
test(0);
}
}
```
```txt
1999 = MCMXCIX
25 = XXV
944 = CMXLIV
Exception in thread "main" java.lang.IllegalArgumentException
at RN.roman(RN.java:15)
at RN.test(RN.java:31)
at RN.main(RN.java:38)
```
```java5
import java.util.Set;
import java.util.EnumSet;
import java.util.Collections;
import java.util.stream.Collectors;
import java.util.stream.LongStream;
public interface RomanNumerals {
public enum Numeral {
M(1000), CM(900), D(500), CD(400), C(100), XC(90), L(50), XL(40), X(10), IX(9), V(5), IV(4), I(1);
public final long weight;
private static final Set SET = Collections.unmodifiableSet(EnumSet.allOf(Numeral.class));
private Numeral(long weight) {
this.weight = weight;
}
public static Numeral getLargest(long weight) {
return SET.stream()
.filter(numeral -> weight >= numeral.weight)
.findFirst()
.orElse(I)
;
}
};
public static String encode(long n) {
return LongStream.iterate(n, l -> l - Numeral.getLargest(l).weight)
.limit(Numeral.values().length)
.filter(l -> l > 0)
.mapToObj(Numeral::getLargest)
.map(String::valueOf)
.collect(Collectors.joining())
;
}
public static long decode(String roman) {
long result = new StringBuilder(roman.toUpperCase()).reverse().chars()
.mapToObj(c -> Character.toString((char) c))
.map(numeral -> Enum.valueOf(Numeral.class, numeral))
.mapToLong(numeral -> numeral.weight)
.reduce(0, (a, b) -> a + (a <= b ? b : -b))
;
if (roman.charAt(0) == roman.charAt(1)) {
result += 2 * Enum.valueOf(Numeral.class, roman.substring(0, 1)).weight;
}
return result;
}
public static void test(long n) {
System.out.println(n + " = " + encode(n));
System.out.println(encode(n) + " = " + decode(encode(n)));
}
public static void main(String[] args) {
LongStream.of(1999, 25, 944).forEach(RomanNumerals::test);
}
}
```
```txt
1999 = MCMXCIX
MCMXCIX = 1999
25 = XXV
XXV = 25
944 = CMXLIV
CMXLIV = 944
```
## JavaScript
### ES5
### =Iteration=
```javascript
var roman = {
map: [
1000, 'M', 900, 'CM', 500, 'D', 400, 'CD', 100, 'C', 90, 'XC',
50, 'L', 40, 'XL', 10, 'X', 9, 'IX', 5, 'V', 4, 'IV', 1, 'I',
],
int_to_roman: function(n) {
var value = '';
for (var idx = 0; n > 0 && idx < this.map.length; idx += 2) {
while (n >= this.map[idx]) {
value += this.map[idx + 1];
n -= this.map[idx];
}
}
return value;
}
}
roman.int_to_roman(1999); // "MCMXCIX"
```
### =Functional composition=
```JavaScript
(function () {
'use strict';
// If the Roman is a string, pass any delimiters through
// (Int | String) -> String
function romanTranscription(a) {
if (typeof a === 'string') {
var ps = a.split(/\d+/),
dlm = ps.length > 1 ? ps[1] : undefined;
return (dlm ? a.split(dlm)
.map(function (x) {
return Number(x);
}) : [a])
.map(roman)
.join(dlm);
} else return roman(a);
}
// roman :: Int -> String
function roman(n) {
return [[1000, "M"], [900, "CM"], [500, "D"], [400, "CD"], [100,
"C"], [90, "XC"], [50, "L"], [40, "XL"], [10, "X"], [9,
"IX"], [5, "V"], [4, "IV"], [1, "I"]]
.reduce(function (a, lstPair) {
var m = a.remainder,
v = lstPair[0];
return (v > m ? a : {
remainder: m % v,
roman: a.roman + Array(
Math.floor(m / v) + 1
)
.join(lstPair[1])
});
}, {
remainder: n,
roman: ''
}).roman;
}
// TEST
return [2016, 1990, 2008, "14.09.2015", 2000, 1666].map(
romanTranscription);
})();
```
```JavaScript
["MMXVI", "MCMXC", "MMVIII", "XIV.IX.MMXV", "MM", "MDCLXVI"]
```
### ES6
(mapAccumL version)
```JavaScript
(() => {
// ROMAN INTEGER STRINGS ----------------------------------------------------
// roman :: Int -> String
const roman = n =>
concat(snd(mapAccumL((balance, [k, v]) => {
const [q, r] = quotRem(balance, v);
return [r, q > 0 ? k.repeat(q) : ''];
}, n, [
['M', 1000],
['CM', 900],
['D', 500],
['CD', 400],
['C', 100],
['XC', 90],
['L', 50],
['XL', 40],
['X', 10],
['IX', 9],
['V', 5],
['IV', 4],
['I', 1]
])));
// GENERIC FUNCTIONS -------------------------------------------------------
// concat :: [[a]] -> [a] | [String] -> String
const concat = xs =>
xs.length > 0 ? (() => {
const unit = typeof xs[0] === 'string' ? '' : [];
return unit.concat.apply(unit, xs);
})() : [];
// map :: (a -> b) -> [a] -> [b]
const map = (f, xs) => xs.map(f);
// 'The mapAccumL function behaves like a combination of map and foldl;
// it applies a function to each element of a list, passing an accumulating
// parameter from left to right, and returning a final value of this
// accumulator together with the new list.' (See Hoogle)
// mapAccumL :: (acc -> x -> (acc, y)) -> acc -> [x] -> (acc, [y])
const mapAccumL = (f, acc, xs) =>
xs.reduce((a, x) => {
const pair = f(a[0], x);
return [pair[0], a[1].concat([pair[1]])];
}, [acc, []]);
// quotRem :: Integral a => a -> a -> (a, a)
const quotRem = (m, n) => [Math.floor(m / n), m % n];
// show :: a -> String
const show = (...x) =>
JSON.stringify.apply(
null, x.length > 1 ? [x[0], null, x[1]] : x
);
// snd :: (a, b) -> b
const snd = tpl => Array.isArray(tpl) ? tpl[1] : undefined;
// TEST -------------------------------------------------------------------
return show(
map(roman, [2016, 1990, 2008, 2000, 1666])
);
})();
```
```JavasCript
["MMXVI","MCMXC","MMVIII","MM","MDCLXVI"]
```
### =Declarative=
```JavaScript
function toRoman(num) {
return 'I'
.repeat(num)
.replace(/IIIII/g, 'V')
.replace(/VV/g, 'X')
.replace(/XXXXX/g, 'L')
.replace(/LL/g, 'C')
.replace(/CCCCC/g, 'D')
.replace(/DD/g, 'M')
.replace(/VIIII/g, 'IX')
.replace(/LXXXX/g, 'XC')
.replace(/XXXX/g, 'XL')
.replace(/DCCCC/g, 'CM')
.replace(/CCCC/g, 'CD')
.replace(/IIII/g, 'IV');
}
console.log(toRoman(1666));
```
```JavaScript>MDCLXVI 0) {
while (n >= this.val[idx]) {
roman += this.ord[idx];
n -= this.val[idx];
}
idx++;
}
return roman;
}
};
provide('Roman', 1);
if (Interp.conf('unitTest')) {
; Roman.fromRoman('VIII');
; Roman.fromRoman('MMMDIV');
; Roman.fromRoman('CDIV');
; Roman.fromRoman('MDCLXVI');
; Roman.fromRoman('not');
; Roman.toRoman(8);
; Roman.toRoman(3504);
; Roman.toRoman(404);
; Roman.toRoman(1666);
}
/*
=!EXPECTSTART!=
Roman.fromRoman('VIII') ==> 8
Roman.fromRoman('MMMDIV') ==> 3504
Roman.fromRoman('CDIV') ==> 404
Roman.fromRoman('MDCLXVI') ==> 1666
Roman.fromRoman('not') ==> NaN
Roman.toRoman(8) ==> VIII
Roman.toRoman(3504) ==> MMMDIV
Roman.toRoman(404) ==> CDIV
Roman.toRoman(1666) ==> MDCLXVI
=!EXPECTEND!=
*/
```
```txt
prompt$ jsish -u Roman.jsi
[PASS] Roman.jsi
```
## Julia
```julia
function romanencode(n::Integer)
if n < 1 || n > 4999 throw(DomainError()) end
DR = [["I", "X", "C", "M"] ["V", "L", "D", "MMM"]]
rnum = ""
for (omag, d) in enumerate(digits(n))
if d == 0
omr = ""
elseif d < 4
omr = DR[omag, 1] ^ d
elseif d == 4
omr = DR[omag, 1] * DR[omag, 2]
elseif d == 5
omr = DR[omag, 2]
elseif d < 9
omr = DR[omag, 2] * DR[omag, 1] ^ (d - 5)
else
omr = DR[omag, 1] * DR[omag + 1, 1]
end
rnum = omr * rnum
end
return rnum
end
testcases = [1990, 2008, 1668]
append!(testcases, rand(1:4999, 12))
testcases = unique(testcases)
println("Test romanencode, arabic => roman:")
for n in testcases
@printf("%-4i => %s\n", n, romanencode(n))
end
```
```txt
Test romanencode, arabic => roman:
1990 => MCMXC
2008 => MMVIII
1668 => MDCLXVIII
2928 => MMCMXXVIII
129 => CXXIX
4217 => MMMMCCXVII
1503 => MDIII
2125 => MMCXXV
1489 => MCDLXXXIX
3677 => MMMDCLXXVII
1465 => MCDLXV
1421 => MCDXXI
1642 => MDCXLII
572 => DLXXII
3714 => MMMDCCXIV
```
## Kotlin
```kotlin
val romanNumerals = mapOf(
1000 to "M",
900 to "CM",
500 to "D",
400 to "CD",
100 to "C",
90 to "XC",
50 to "L",
40 to "XL",
10 to "X",
9 to "IX",
5 to "V",
4 to "IV",
1 to "I"
)
fun encode(number: Int): String? {
if (number > 5000 || number < 1) {
return null
}
var num = number
var result = ""
for ((multiple, numeral) in romanNumerals.entries) {
while (num >= multiple) {
num -= multiple
result += numeral
}
}
return result
}
fun main(args: Array) {
println(encode(1990))
println(encode(1666))
println(encode(2008))
}
```
```txt
MCMXC
MDCLXVI
MMVIII
```
Alternatively:
```kotlin
fun Int.toRomanNumeral(): String {
fun digit(k: Int, unit: String, five: String, ten: String): String {
return when (k) {
in 1..3 -> unit.repeat(k)
4 -> unit + five
in 5..8 -> five + unit.repeat(k - 5)
9 -> unit + ten
else -> throw IllegalArgumentException("$k not in range 1..9")
}
}
return when (this) {
0 -> ""
in 1..9 -> digit(this, "I", "V", "X")
in 10..99 -> digit(this / 10, "X", "L", "C") + (this % 10).toRomanNumeral()
in 100..999 -> digit(this / 100, "C", "D", "M") + (this % 100).toRomanNumeral()
in 1000..3999 -> "M" + (this - 1000).toRomanNumeral()
else -> throw IllegalArgumentException("${this} not in range 0..3999")
}
}
```
## Lasso
```Lasso>define br =
'\r'
// encode roman
define encodeRoman(num::integer)::string => {
local(ref = array('M'=1000, 'CM'=900, 'D'=500, 'CD'=400, 'C'=100, 'XC'=90, 'L'=50, 'XL'=40, 'X'=10, 'IX'=9, 'V'=5, 'IV'=4, 'I'=1))
local(out = string)
with i in #ref do => {
while(#num >= #i->second) => {
#out->append(#i->first)
#num -= #i->second
}
}
return #out
}
'1990 in roman is '+encodeRoman(1990)
br
'2008 in roman is '+encodeRoman(2008)
br
'1666 in roman is '+encodeRoman(1666)
```
## LaTeX
The macro \Roman is defined for uppercase roman numeral, accepting as ''argument'' a name of an existing counter.
```latex
\documentclass{article}
\begin{document}
\newcounter{currentyear}\setcounter{currentyear}{\year}
Anno Domini \Roman{currentyear}
\end{document}
```
## Liberty BASIC
```lb
dim arabic( 12)
for i =0 to 12
read k
arabic( i) =k
next i
data 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1
dim roman$( 12)
for i =0 to 12
read k$
roman$( i) =k$
next i
data "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"
print 2009, toRoman$( 2009)
print 1666, toRoman$( 1666)
print 3888, toRoman$( 3888)
end
function toRoman$( value)
i =0
result$ =""
for i = 0 to 12
while value >=arabic( i)
result$ = result$ + roman$( i)
value = value - arabic( i)
wend
next i
toRoman$ =result$
end function
```
```txt
2009 MMIX
1666 MDCLXVI
3888 MMMDCCCLXXXVIII
```
## LiveCode
```LiveCode
function toRoman intNum
local roman,numArabic
put "M,CM,D,CD,C,XC,L,XL,X,IX,V,IV,I" into romans
put "1000,900,500,400,100,90,50,40,10,9,5,4,1" into arabics
put intNum into numArabic
repeat with n = 1 to the number of items of romans
put numArabic div item n of arabics into nums
if nums > 0 then
put repeatChar(item n of romans,nums) after roman
add -(nums * item n of arabics) to numArabic
end if
end repeat
return roman
end toRoman
function repeatChar c n
local cc
repeat n times
put c after cc
end repeat
return cc
end repeatChar
```
Examples
```txt
toRoman(2009) -- MMIX
toRoman(1666) -- MDCLXVI
toRoman(1984) -- MCMLXXXIV
toRoman(3888) -- MMMDCCCLXXXVIII
```
## Logo
```logo
make "roman.rules [
[1000 M] [900 CM] [500 D] [400 CD]
[ 100 C] [ 90 XC] [ 50 L] [ 40 XL]
[ 10 X] [ 9 IX] [ 5 V] [ 4 IV]
[ 1 I]
]
to roman :n [:rules :roman.rules] [:acc "||]
if empty? :rules [output :acc]
if :n < first first :rules [output (roman :n bf :rules :acc)]
output (roman :n - first first :rules :rules word :acc last first :rules)
end
```
```logo
make "patterns [[?] [? ?] [? ? ?] [? ?2] [?2] [?2 ?] [?2 ? ?] [?2 ? ? ?] [? ?3]]
to digit :d :numerals
if :d = 0 [output "||]
output apply (sentence "\( "word (item :d :patterns) "\)) :numerals
end
to digits :n :numerals
output word ifelse :n < 10 ["||] [digits int :n/10 bf bf :numerals] ~
digit modulo :n 10 :numerals
end
to roman :n
if or :n < 0 :n >= 4000 [output [EX MODVS!]]
output digits :n [I V X L C D M]
end
print roman 1999 ; MCMXCIX
print roman 25 ; XXV
print roman 944 ; CMXLIV
```
## LotusScript
```lss
Function toRoman(value) As String
Dim arabic(12) As Integer
Dim roman(12) As String
arabic(0) = 1000
arabic(1) = 900
arabic(2) = 500
arabic(3) = 400
arabic(4) = 100
arabic(5) = 90
arabic(6) = 50
arabic(7) = 40
arabic(8) = 10
arabic(9) = 9
arabic(10) = 5
arabic(11) = 4
arabic(12) = 1
roman(0) = "M"
roman(1) = "CM"
roman(2) = "D"
roman(3) = "CD"
roman(4) = "C"
roman(5) = "XC"
roman(6) = "L"
roman(7) = "XL"
roman(8) = "X"
roman(9) = "IX"
roman(10) = "V"
roman(11) = "IV"
roman(12) = "I"
Dim i As Integer, result As String
For i = 0 To 12
Do While value >= arabic(i)
result = result + roman(i)
value = value - arabic(i)
Loop
Next i
toRoman = result
End Function
```
## Lua
```lua
romans = {
{1000, "M"},
{900, "CM"}, {500, "D"}, {400, "CD"}, {100, "C"},
{90, "XC"}, {50, "L"}, {40, "XL"}, {10, "X"},
{9, "IX"}, {5, "V"}, {4, "IV"}, {1, "I"} }
k = io.read() + 0
for _, v in ipairs(romans) do --note that this is -not- ipairs.
val, let = unpack(v)
while k >= val do
k = k - val
io.write(let)
end
end
print()
```
## M4
```M4
define(`roman',`ifelse(eval($1>=1000),1,`M`'roman(eval($1-1000))',
`ifelse(eval($1>=900),1,`CM`'roman(eval($1-900))',
`ifelse(eval($1>=500),1,`D`'roman(eval($1-500))',
`ifelse(eval($1>=100),1,`C`'roman(eval($1-100))',
`ifelse(eval($1>=90),1,`XC`'roman(eval($1-90))',
`ifelse(eval($1>=50),1,`L`'roman(eval($1-50))',
`ifelse(eval($1>=40),1,`XL`'roman(eval($1-40))',
`ifelse(eval($1>=10),1,`X`'roman(eval($1-10))',
`ifelse(eval($1>=9),1,`IX`'roman(eval($1-9))',
`ifelse(eval($1>=5),1,`V`'roman(eval($1-5))',
`ifelse(eval($1>=4),1,`IV`'roman(eval($1-4))',
`ifelse(eval($1>=1),1,`I`'roman(eval($1-1))'
)')')')')')')')')')')')')dnl
dnl
roman(3675)
```
```txt
MMMDCLXXV
```
## Maple
```Maple>
for n in [ 1666, 1990, 2008 ] do printf( "%d\t%s\n", n, convert( n, 'roman' ) ) end:
1666 MDCLXVI
1990 MCMXC
2008 MMVIII
```
## Mathematica
RomanNumeral is a built-in function in the Wolfram language
Examples:
```Mathematica
RomanNumeral[4]
RomanNumeral[99]
RomanNumeral[1337]
RomanNumeral[1666]
RomanNumeral[6889]
```
gives back:
```Mathematica
IV
XCIX
MCCCXXXVII
MDCLXVI
MMMMMMDCCCLXXXIX
```
== {{header|Mercury}} ==
The non-ceremonial work in this program starts at the function to_roman/1. Unusually for Mercury the function is semi-deterministic. This is because some of the helper functions it calls are also semi-deterministic and the determinism subsystem propagates the status upward. (There are ways to stop it from doing this, but it would distract from the actual Roman numeral conversion process so the semi-determinism has been left in.)
to_roman/1 is just a string of chained function calls. The number is passed in as a string (and the main/2 predicate ensures that it is *only* digits!) is converted into a list of characters. This list is then reversed and the Roman numeral version is built from it. This resulting character list is then converted back into a string and returned.
build_roman/1 takes the lead character off the list (reversed numerals) and then recursively calls itself. It uses the promote/2 predicate to multiply the ensuing Roman numerals (if any) by an order of magnitude and converts the single remaining digit to the appropriate list of Roman numerals. To clarify, if it's passed the number "123" (encoded by this point as ['3', '2', '1']) the following transpires:
* The '3' is removed and build_roman/1 is now called with ['2', '1'].
** The '2' is removed and the function is recursively called with ['1'].
*** The '1' is removed and the function is recursively called with [] (the empty list)..
**** The function returns [].
*** The [] has its (non-existent) digits promoted and then gets ['I'] appended (1 converts to ['I'] via digit_to_roman/1).
** The ['I'] has its (single) digit promoted and is converted to ['X'] and then gets ['I','I'] appended from the 2's conversion. The resulting list is now ['X','I','I'] (or 12).
* The ['X','I','I'] has all of its digits promoted, yielding ['C','X','X'] before getting ['I','I','I'] appended. The resulting list is now ['C','X','X','I','I','I'] which is converted into the string "CXXIII" back up in to_roman/1.
It is possible for this to be implemented differently even keeping the same algorithm. For example the map module from the standard library could be used for looking up conversions and promotions instead of having digit_to_roman/1 and promote. This would require, however, either passing around the conversion tables constantly (bulking up the parameter lists of all functions and predicates) or creating said conversion tables each time at point of use (slowing down the implementation greatly).
Now the semi-determinism of the functions involved is a little bit of a problem. In the main/2 predicate you can see one means of dealing with it. main/2 *must* be deterministic (or cc_multi, but this is equivalent for this discussion). There can be *no* failure in a called function or predicate … unless that failure is explicitly handled somehow. In this implementation the failure is handled in the foldl/4's provided higher-order predicate lambda. The call to to_roman/1 is called within a conditional and both the success (true) and failure (false) branches are handled. This makes the passed-in predicate lambda deterministic, even though the implementation functions and predicates are semi-deterministic.
But why are they semi-deterministic? Well, this has to do with the type system. It doesn't permit sub-typing, so when the type of a predicate is, say pred(char, char) (as is the case for promote/2), the underlying implementation *must* handle *all* values that a type char could possibly hold. It is trivial to see that our code does not. This means that, in theory, it is possible that promote/2 (or digit_to_roman/1) could be passed a value which cannot be processed, thus triggering a false result, and thus being semi-deterministic.
### roman.m
```Mercury
:- module roman.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is det.
:- implementation.
:- import_module char, int, list, string.
main(!IO) :-
command_line_arguments(Args, !IO),
filter(is_all_digits, Args, CleanArgs),
foldl((pred(Arg::in, !.IO::di, !:IO::uo) is det :-
( Roman = to_roman(Arg) ->
format("%s => %s", [s(Arg), s(Roman)], !IO), nl(!IO)
; format("%s cannot be converted.", [s(Arg)], !IO), nl(!IO) )
), CleanArgs, !IO).
:- func to_roman(string::in) = (string::out) is semidet.
to_roman(Number) = from_char_list(build_roman(reverse(to_char_list(Number)))).
:- func build_roman(list(char)) = list(char).
:- mode build_roman(in) = out is semidet.
build_roman([]) = [].
build_roman([D|R]) = Roman :-
map(promote, build_roman(R), Interim),
Roman = Interim ++ digit_to_roman(D).
:- func digit_to_roman(char) = list(char).
:- mode digit_to_roman(in) = out is semidet.
digit_to_roman('0') = [].
digit_to_roman('1') = ['I'].
digit_to_roman('2') = ['I','I'].
digit_to_roman('3') = ['I','I','I'].
digit_to_roman('4') = ['I','V'].
digit_to_roman('5') = ['V'].
digit_to_roman('6') = ['V','I'].
digit_to_roman('7') = ['V','I','I'].
digit_to_roman('8') = ['V','I','I','I'].
digit_to_roman('9') = ['I','X'].
:- pred promote(char::in, char::out) is semidet.
promote('I', 'X').
promote('V', 'L').
promote('X', 'C').
promote('L', 'D').
promote('C', 'M').
:- end_module roman.
```
```txt
$ '''mmc roman && ./roman 1 8 27 64 125 216 343 512 729 1000 1331 1728 2197 2744 3375'''
''1 => I''
''8 => VIII''
''27 => XXVII''
''64 => LXIV''
''125 => CXXV''
''216 => CCXVI''
''343 => CCCXLIII''
''512 => DXII''
''729 => DCCXXIX''
''1000 => M''
''1331 => MCCCXXXI''
''1728 => MDCCXXVIII''
''2197 => MMCXCVII''
''2744 => MMDCCXLIV''
''3375 => MMMCCCLXXV''
```
### roman2.m
Another implementation using an algorithm inspired by [[#Erlang|the Erlang implementation]] could look like this:
```Mercury
:- module roman2.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is det.
:- implementation.
:- import_module char, int, list, string.
main(!IO) :-
command_line_arguments(Args, !IO),
filter_map(to_int, Args, CleanArgs),
foldl((pred(Arg::in, !.IO::di, !:IO::uo) is det :-
( Roman = to_roman(Arg) ->
format("%i => %s",
[i(Arg), s(from_char_list(Roman))], !IO),
nl(!IO)
; format("%i cannot be converted.", [i(Arg)], !IO), nl(!IO) )
), CleanArgs, !IO).
:- func to_roman(int) = list(char).
:- mode to_roman(in) = out is semidet.
to_roman(N) = ( N >= 1000 ->
['M'] ++ to_roman(N - 1000)
;( N >= 100 ->
digit(N / 100, 'C', 'D', 'M') ++ to_roman(N rem 100)
;( N >= 10 ->
digit(N / 10, 'X', 'L', 'C') ++ to_roman(N rem 10)
;( N >= 1 ->
digit(N, 'I', 'V', 'X')
; [] ) ) ) ).
:- func digit(int, char, char, char) = list(char).
:- mode digit(in, in, in, in) = out is semidet.
digit(1, X, _, _) = [X].
digit(2, X, _, _) = [X, X].
digit(3, X, _, _) = [X, X, X].
digit(4, X, Y, _) = [X, Y].
digit(5, _, Y, _) = [Y].
digit(6, X, Y, _) = [Y, X].
digit(7, X, Y, _) = [Y, X, X].
digit(8, X, Y, _) = [Y, X, X, X].
digit(9, X, _, Z) = [X, Z].
:- end_module roman2.
```
This implementation calculates the value of the thousands, then the hundreds, then the tens, then the ones. In each case it uses the digit/4 function and some tricks with unification to build the appropriate list of characters for the digit and multiplier being targeted.
Its output is identical to that of the previous version.
## Microsoft Small Basic
```microsoftsmallbasic
arabicNumeral = 1990
ConvertToRoman()
TextWindow.WriteLine(romanNumeral) 'MCMXC
arabicNumeral = 2018
ConvertToRoman()
TextWindow.WriteLine(romanNumeral) 'MMXVIII
arabicNumeral = 3888
ConvertToRoman()
TextWindow.WriteLine(romanNumeral) 'MMMDCCCLXXXVIII
Sub ConvertToRoman
weights[0] = 1000
weights[1] = 900
weights[2] = 500
weights[3] = 400
weights[4] = 100
weights[5] = 90
weights[6] = 50
weights[7] = 40
weights[8] = 10
weights[9] = 9
weights[10] = 5
weights[11] = 4
weights[12] = 1
symbols[0] = "M"
symbols[1] = "CM"
symbols[2] = "D"
symbols[3] = "CD"
symbols[4] = "C"
symbols[5] = "XC"
symbols[6] = "L"
symbols[7] = "XL"
symbols[8] = "X"
symbols[9] = "IX"
symbols[10] = "V"
symbols[11] = "IV"
symbols[12] = "I"
romanNumeral = ""
i = 0
While (i <= 12) And (arabicNumeral > 0)
While arabicNumeral >= weights[i]
romanNumeral = Text.Append(romanNumeral, symbols[i])
arabicNumeral = arabicNumeral - weights[i]
EndWhile
i = i + 1
EndWhile
EndSub
```
```txt
MCMXC
MMXVIII
MMMDCCCLXXXVIII
```
=={{header|Modula-2}}==
```modula2
MODULE RomanNumeralsEncode;
FROM Strings IMPORT
Append;
FROM STextIO IMPORT
WriteString, WriteLn;
CONST
MaxChars = 15;
(* 3888 or MMMDCCCLXXXVIII (15 chars) is the longest string properly encoded
with these symbols. *)
TYPE
TRomanNumeral = ARRAY [0 .. MaxChars - 1] OF CHAR;
PROCEDURE ToRoman(AValue: CARDINAL; VAR OUT Destination: ARRAY OF CHAR);
TYPE
TRomanSymbols = ARRAY [0 .. 1] OF CHAR;
TWeights = ARRAY [0 .. 12] OF CARDINAL;
TSymbols = ARRAY [0 .. 12] OF TRomanSymbols;
CONST
Weights = TWeights {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
Symbols = TSymbols {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX",
"V", "IV", "I"};
VAR
I: CARDINAL;
BEGIN
Destination := "";
I := 0;
WHILE (I <= HIGH(Weights)) AND (AValue > 0) DO
WHILE AValue >= Weights[I] DO
Append(Symbols[I], Destination);
AValue := AValue - Weights[I]
END;
INC(I);
END;
END ToRoman;
VAR
Numeral: TRomanNumeral;
BEGIN
ToRoman(1990, Numeral); WriteString(Numeral); WriteLn; (* MCMXC *)
ToRoman(2018, Numeral); WriteString(Numeral); WriteLn; (* MMXVIII *)
ToRoman(3888, Numeral); WriteString(Numeral); WriteLn; (* MMMDCCCLXXXVIII *)
END RomanNumeralsEncode.
```
```txt
MCMXC
MMXVIII
MMMDCCCLXXXVIII
```
## MUMPS
```MUMPS
TOROMAN(INPUT)
;Converts INPUT into a Roman numeral. INPUT must be an integer between 1 and 3999
;OUTPUT is the string to return
;I is a loop variable
;CURRVAL is the current value in the loop
QUIT:($FIND(INPUT,".")>1)!(INPUT<=0)!(INPUT>3999) "Invalid input"
NEW OUTPUT,I,CURRVAL
SET OUTPUT="",CURRVAL=INPUT
SET:$DATA(ROMANNUM)=0 ROMANNUM="I^IV^V^IX^X^XL^L^XC^C^CD^D^CM^M"
SET:$DATA(ROMANVAL)=0 ROMANVAL="1^4^5^9^10^40^50^90^100^400^500^900^1000"
FOR I=$LENGTH(ROMANVAL,"^"):-1:1 DO
.FOR Q:CURRVAL<$PIECE(ROMANVAL,"^",I) SET OUTPUT=OUTPUT_$PIECE(ROMANNUM,"^",I),CURRVAL=CURRVAL-$PIECE(ROMANVAL,"^",I)
KILL I,CURRVAL
QUIT OUTPUT
```
```txt
USER>W $$ROMAN^ROSETTA(1666)
MDCLXVI
USER>W $$TOROMAN^ROSETTA(2010)
MMX
USER>W $$TOROMAN^ROSETTA(949)
CMXLIX
USER>W $$TOROMAN^ROSETTA(949.24)
Invalid input
USER>W $$TOROMAN^ROSETTA(-949)
Invalid input
```
Another variant
```MUMPS
TOROMAN(n)
;return empty string if input parameter 'n' is not in 1-3999
Quit:(n'?1.4N)!(n'<4000)!'n ""
New r Set r=""
New p Set p=$Length(n)
New j,x
For j=1:1:p Do
. Set x=$Piece("~I~II~III~IV~V~VI~VII~VIII~IX","~",$Extract(n,j)+1)
. Set x=$Translate(x,"IVX",$Piece("IVX~XLC~CDM~M","~",p-j+1))
. Set r=r_x
Quit r
```
## Nim
```nim
import strutils
const nums = [(1000, "M"), (900, "CM"), (500, "D"), (400, "CD"), (100, "C"), (90, "XC"),
(50, "L"), (40, "XL"), (10, "X"), (9, "IX"), (5, "V"), (4, "IV"), (1, "I")]
proc toRoman(x): string =
var x = x
result = ""
for a,r in items(nums):
result.add(repeatStr(x div a, r))
x = x mod a
for i in [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,25,30,40,
50,60,69,70,80,90,99,100,200,300,400,500,600,666,700,800,900,
1000,1009,1444,1666,1945,1997,1999,2000,2008,2010,2011,2500,
3000,3999]:
echo toRoman(i)
```
## Objeck
```objeck
bundle Default {
class Roman {
nums: static : Int[];
rum : static : String[];
function : Init() ~ Nil {
nums := [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];
rum := ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"];
}
function : native : ToRoman(number : Int) ~ String {
result := "";
for(i :=0; i < nums->Size(); i += 1;) {
while(number >= nums[i]) {
result->Append(rum[i]);
number -= nums[i];
};
};
return result;
}
function : Main(args : String[]) ~ Nil {
Init();
ToRoman(1999)->PrintLine();
ToRoman(25)->PrintLine();
ToRoman(944)->PrintLine();
}
}
}
```
## OCaml
With an explicit decimal digit representation list:
```ocaml
let digit x y z = function
1 -> [x]
| 2 -> [x;x]
| 3 -> [x;x;x]
| 4 -> [x;y]
| 5 -> [y]
| 6 -> [y;x]
| 7 -> [y;x;x]
| 8 -> [y;x;x;x]
| 9 -> [x;z]
let rec to_roman x =
if x = 0 then []
else if x < 0 then
invalid_arg "Negative roman numeral"
else if x >= 1000 then
'M' :: to_roman (x - 1000)
else if x >= 100 then
digit 'C' 'D' 'M' (x / 100) @ to_roman (x mod 100)
else if x >= 10 then
digit 'X' 'L' 'C' (x / 10) @ to_roman (x mod 10)
else
digit 'I' 'V' 'X' x
```
```txt
# to_roman 1999;;
- : char list = ['M'; 'C'; 'M'; 'X'; 'C'; 'I'; 'X']
# to_roman 25;;
- : char list = ['X'; 'X'; 'V']
# to_roman 944;;
- : char list = ['C'; 'M'; 'X'; 'L'; 'I'; 'V']
```
## Oforth
```Oforth
[ [1000,"M"], [900,"CM"], [500,"D"], [400,"CD"], [100,"C"], [90,"XC"], [50,"L"], [40,"XL"], [10,"X"], [9,"IX"], [5,"V"], [4,"IV"], [1,"I"] ] const: Romans
: roman(n)
| r |
StringBuffer new
Romans forEach: r [ while(r first n <=) [ r second << n r first - ->n ] ] ;
```
## OpenEdge/Progress
```progress
FUNCTION encodeRoman RETURNS CHAR (
i_i AS INT
):
DEF VAR cresult AS CHAR.
DEF VAR croman AS CHAR EXTENT 7 INIT [ "M", "D", "C", "L", "X", "V", "I" ].
DEF VAR idecimal AS INT EXTENT 7 INIT [ 1000, 500, 100, 50, 10, 5, 1 ].
DEF VAR ipos AS INT INIT 1.
DO WHILE i_i > 0:
IF i_i - idecimal[ ipos ] >= 0 THEN
ASSIGN
cresult = cresult + croman[ ipos ]
i_i = i_i - idecimal[ ipos ]
.
ELSE IF ipos < EXTENT( croman ) - 1 AND i_i - ( idecimal[ ipos ] - idecimal[ ipos + 2 ] ) >= 0 THEN
ASSIGN
cresult = cresult + croman[ ipos + 2 ] + croman[ ipos ]
i_i = i_i - ( idecimal[ ipos ] - idecimal[ ipos + 2 ] )
ipos = ipos + 1
.
ELSE
ipos = ipos + 1.
END.
RETURN cresult.
END FUNCTION. /* encodeRoman */
MESSAGE
1990 encodeRoman( 1990 ) SKIP
2008 encodeRoman( 2008 ) SKIP
2000 encodeRoman( 2000 ) SKIP
1666 encodeRoman( 1666 ) SKIP
VIEW-AS ALERT-BOX.
```
```txt
---------------------------
Message (Press HELP to view stack trace)
---------------------------
1990 MCMXC
2008 MMVIII
2000 MM
1666 MDCLXVI
---------------------------
OK Help
---------------------------
```
## Oz
```oz
declare
fun {Digit X Y Z K}
unit([X] [X X] [X X X] [X Y] [Y] [Y X] [Y X X] [Y X X X] [X Z])
.K
end
fun {ToRoman X}
if X == 0 then ""
elseif X < 0 then raise toRoman(negativeInput X) end
elseif X >= 1000 then "M"#{ToRoman X-1000}
elseif X >= 100 then {Digit &C &D &M X div 100}#{ToRoman X mod 100}
elseif X >= 10 then {Digit &X &L &C X div 10}#{ToRoman X mod 10}
else {Digit &I &V &X X}
end
end
in
{ForAll {Map [1999 25 944] ToRoman} System.showInfo}
```
## PARI/GP
Old-style Roman numerals
```parigp
oldRoman(n)={
while(n>999999,
n-=1000000;
print1("((((I))))")
);
if(n>499999,
n-=500000;
print1("I))))")
);
while(n>99999,
n-=100000;
print1("(((I)))")
);
if(n>49999,
n-=50000;
print1("I)))")
);
while(n>9999,
n-=10000;
print1("((I))")
);
if(n>4999,
n-=5000;
print1("I))")
);
while(n>999,
n-=1000;
print1("(I)")
);
if(n>499,
n-=500;
print1("I)")
);
while(n>99,
n-=100;
print1("C")
);
if(n>49,
n-=50;
print1("L");
);
while(n>9,
n-=10;
print1("X")
);
if(n>4,
n-=5;
print1("V");
);
while(n,
n--;
print1("I")
);
print()
};
```
This simple version of medieval Roman numerals does not handle large numbers.
```parigp
medievalRoman(n)={
while(n>999,
n-=1000;
print1("M")
);
if(n>899,
n-=900;
print1("CM")
);
if(n>499,
n-=500;
print1("D")
);
if(n>399,
n-=400;
print1("CD")
);
while(n>99,
n-=100;
print1("C")
);
if(n>89,
n-=90;
print1("XC")
);
if(n>49,
n-=50;
print1("L")
);
if(n>39,
n-=40;
print1("XL")
);
while(n>9,
n-=10;
print1("X")
);
if(n>8,
n-=9;
print1("IX")
);
if(n>4,
n-=5;
print1("V")
);
if(n>3,
n-=4;
print1("IV")
);
while(n,
n--;
print1("I")
);
print()
};
```
## Pascal
See [[Roman_numerals/Encode#Delphi | Delphi]]
## Peloton
Roman numbers are built in to Peloton as a particular form of national number. However, for the sake of the task the _RO opcode has been defined.
```sgml><@ DEFUDOLITLIT
_RO|__Transformer|<@ DEFKEYPAR>__NationalNumericID|2<@ LETRESCS%NNMPAR>...|1
<@ ENU$$DLSTLITLIT>1990,2008,1,2,64,124,1666,10001|,|
<@ SAYELTLST>... is <@ SAY_ROELTLSTLIT>...|RomanLowerUnicode <@ SAY_ROELTLSTLIT>...|RomanUpperUnicode <@ SAY_ROELTLSTLIT>...|RomanASCII
```
Same code in padded-out, variable-length English dialect
```sgml><# DEFINE USERDEFINEDOPCODE LITERAL LITERAL
_RO|__Transformer|<# DEFINE KEYWORD PARAMETER>__NationalNumericID|2<# LET RESULT CAST NATIONALNUMBER PARAMETER>...|1
<# ENUMERATION LAMBDASPECIFIEDDELMITER LIST LITERAL LITERAL>1990,2008,1,2,64,124,1666,10001|,|
<# SAY ELEMENT LIST>... is <# SAY _RO ELEMENT LIST LITERAL>...|RomanLowerUnicode <# SAY _RO ELEMENT LIST LITERAL>...|RomanUpperUnicode <# SAY _RO ELEMENT LIST LITERAL>...|RomanASCII
```
{{out}} Notice here the three different ways of representing the results.
For reasons for notational differences, see [[wp:Roman_numerals#Alternate_forms]]
```txt
1990 is ⅿⅽⅿⅹⅽ ⅯⅭⅯⅩⅭ MCMXC
2008 is ⅿⅿⅷ ⅯⅯⅧ MMVIII
1 is ⅰ Ⅰ I
2 is ⅱ Ⅱ II
64 is ⅼⅹⅳ ⅬⅩⅣ LXIV
124 is ⅽⅹⅹⅳ ⅭⅩⅩⅣ CXXIV
1666 is ⅿⅾⅽⅼⅹⅵ ⅯⅮⅭⅬⅩⅥ MDCLXVI
10001 is ⅿⅿⅿⅿⅿⅿⅿⅿⅿⅿⅰ ↂⅠ MMMMMMMMMMI
```
## Perl
### = Simple program =
Simple, fast, produces same output as the Math::Roman module and the Perl 6 example, less crazy than writing a Latin program, and doesn't require experimental modules like the Perl 6 translation.
```perl
my @symbols = ( [1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50, 'L'], [40, 'XL'], [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I'] );
sub roman {
my($n, $r) = (shift, '');
($r, $n) = ('-', -$n) if $n < 0; # Optional handling of negative input
foreach my $s (@symbols) {
my($arabic, $roman) = @$s;
($r, $n) = ($r .= $roman x int($n/$arabic), $n % $arabic)
if $n >= $arabic;
}
$r;
}
say roman($_) for 1..2012;
```
### = Using a module =
```perl
use Math::Roman qw/roman/;
say roman($_) for 1..2012'
```
### = Ported version of Perl6 =
```perl
use List::MoreUtils qw( natatime );
my %symbols = (
1 => "I", 5 => "V", 10 => "X", 50 => "L", 100 => "C",
500 => "D", 1_000 => "M"
);
my @subtractors = (
1_000, 100, 500, 100, 100, 10, 50, 10, 10, 1, 5, 1, 1, 0
);
sub roman {
return '' if 0 == (my $n = shift);
my $iter = natatime 2, @subtractors;
while( my ($cut, $minus) = $iter->() ) {
$n >= $cut
and return $symbols{$cut} . roman($n - $cut);
$n >= $cut - $minus
and return $symbols{$minus} . roman($n + $minus);
}
};
print roman($_) . "\n" for 1..2012;
```
## Perl 6
```perl6
my %symbols =
1 => "I", 5 => "V", 10 => "X", 50 => "L", 100 => "C",
500 => "D", 1_000 => "M";
my @subtractors =
1_000, 100, 500, 100, 100, 10, 50, 10, 10, 1, 5, 1, 1, 0;
multi sub roman (0) { '' }
multi sub roman (Int $n) {
for @subtractors -> $cut, $minus {
$n >= $cut
and return %symbols{$cut} ~ roman($n - $cut);
$n >= $cut - $minus
and return %symbols{$minus} ~ roman($n + $minus);
}
}
# Sample usage
for 1 .. 2_010 -> $x {
say roman($x);
}
```
## Phix
copied from Euphoria
```Phix
constant roman = {"M", "CM", "D","CD", "C","XC","L","XL","X","IX","V","IV","I"}
constant decml = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 }
function toRoman(integer val)
string res = ""
for i=1 to length(roman) do
while val>=decml[i] do
res &= roman[i]
val -= decml[i]
end while
end for
return res
end function
```
## PHP
```php
/**
* int2roman
* Convert any positive value of a 32-bit signed integer to its modern roman
* numeral representation. Numerals within parentheses are multiplied by
* 1000. ie. M == 1 000, (M) == 1 000 000, ((M)) == 1 000 000 000
*
* @param number - an integer between 1 and 2147483647
* @return roman numeral representation of number
*/
function int2roman($number)
{
if (!is_int($number) || $number < 1) return false; // ignore negative numbers and zero
$integers = array(900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1);
$numerals = array('CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I');
$major = intval($number / 1000) * 1000;
$minor = $number - $major;
$numeral = $leastSig = '';
for ($i = 0; $i < sizeof($integers); $i++) {
while ($minor >= $integers[$i]) {
$leastSig .= $numerals[$i];
$minor -= $integers[$i];
}
}
if ($number >= 1000 && $number < 40000) {
if ($major >= 10000) {
$numeral .= '(';
while ($major >= 10000) {
$numeral .= 'X';
$major -= 10000;
}
$numeral .= ')';
}
if ($major == 9000) {
$numeral .= 'M(X)';
return $numeral . $leastSig;
}
if ($major == 4000) {
$numeral .= 'M(V)';
return $numeral . $leastSig;
}
if ($major >= 5000) {
$numeral .= '(V)';
$major -= 5000;
}
while ($major >= 1000) {
$numeral .= 'M';
$major -= 1000;
}
}
if ($number >= 40000) {
$major = $major/1000;
$numeral .= '(' . int2roman($major) . ')';
}
return $numeral . $leastSig;
}
```
## PicoLisp
```PicoLisp
(de roman (N)
(pack
(make
(mapc
'((C D)
(while (>= N D)
(dec 'N D)
(link C) ) )
'(M CM D CD C XC L XL X IX V IV I)
(1000 900 500 400 100 90 50 40 10 9 5 4 1) ) ) ) )
```
```txt
: (roman 1009)
-> "MIX"
: (roman 1666)
-> "MDCLXVI"
```
## Pike
```pike
import String;
int main(){
write(int2roman(2009) + "\n");
write(int2roman(1666) + "\n");
write(int2roman(1337) + "\n");
}
```
## plainTeX
TeX has its own way to convert a number into roman numeral, but it produces lowercase letters; the following macro (and usage example), produce uppercase roman numeral.
```tex
\def\upperroman#1{\uppercase\expandafter{\romannumeral#1}}
Anno Domini \upperroman{\year}
\bye
```
## PL/I
```PL/I
/* From Wiki Fortran */
roman: procedure (n) returns(character (32) varying);
declare n fixed binary nonassignable;
declare (d, m) fixed binary;
declare (r, m_div) character (32) varying;
declare d_dec(13) fixed binary static initial
(1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1);
declare d_rom(13) character (2) varying static initial
('M', 'CM', 'D', 'CD', 'C', 'XC', 'L',
'XL', 'X', 'IX', 'V', 'IV', 'I');
r = '';
m = n;
do d = 1 to 13;
m_div = m / d_dec (d);
r = r || copy (d_rom (d), m_div);
m = m - d_dec (d) * m_div;
end;
return (r);
end roman;
```
Results:
```txt
11 XI
1990 MCMXC
2008 MMVIII
1666 MDCLXVI
1999 MCMXCIX
```
## PL/SQL
```PL/SQL
/*****************************************************************
* $Author: Atanas Kebedjiev $
*****************************************************************
* Encoding an Arabic numeral to a Roman in the range 1..3999 is much simpler as Oracle provides the conversion formats.
* Please see also the SQL solution for the same task.
*/
CREATE OR REPLACE
FUNCTION rencode(an IN NUMBER)
RETURN VARCHAR2
IS
BEGIN
RETURN to_char(an, 'RN');
END rencode;
BEGIN
DBMS_OUTPUT.PUT_LINE ('2012 = ' || rencode('2012')); -- MMXII
DBMS_OUTPUT.PUT_LINE ('1951 = ' || rencode('1951')); -- MCMLI
DBMS_OUTPUT.PUT_LINE ('1987 = ' || rencode('1987')); -- MCMLXXXVII
DBMS_OUTPUT.PUT_LINE ('1666 = ' || rencode('1666')); -- MDCLXVI
DBMS_OUTPUT.PUT_LINE ('1999 = ' || rencode('1999')); -- MCMXCIX
END;
```
## PowerBASIC
```powerbasic
FUNCTION toRoman(value AS INTEGER) AS STRING
DIM arabic(0 TO 12) AS INTEGER
DIM roman(0 TO 12) AS STRING
ARRAY ASSIGN arabic() = 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1
ARRAY ASSIGN roman() = "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"
DIM i AS INTEGER
DIM result AS STRING
FOR i = 0 TO 12
DO WHILE value >= arabic(i)
result = result & roman(i)
value = value - arabic(i)
LOOP
NEXT i
toRoman = result
END FUNCTION
FUNCTION PBMAIN
'Testing
? "2009 = " & toRoman(2009)
? "1666 = " & toRoman(1666)
? "3888 = " & toRoman(3888)
END FUNCTION
```
## PowerShell
```PowerShell
function ConvertTo-RomanNumeral
{
<#
.SYNOPSIS
Converts a number to a Roman numeral.
.DESCRIPTION
Converts a number - in the range of 1 to 3,999 - to a Roman numeral.
.PARAMETER Number
An integer in the range 1 to 3,999.
.INPUTS
System.Int32
.OUTPUTS
System.String
.EXAMPLE
ConvertTo-RomanNumeral -Number (Get-Date).Year
.EXAMPLE
(Get-Date).Year | ConvertTo-RomanNumeral
#>
[CmdletBinding()]
[OutputType([string])]
Param
(
[Parameter(Mandatory=$true,
HelpMessage="Enter an integer in the range 1 to 3,999",
ValueFromPipeline=$true,
Position=0)]
[ValidateRange(1,3999)]
[int]
$Number
)
Begin
{
$DecimalToRoman = @{
Thousands = "","M","MM","MMM"
Hundreds = "","C","CC","CCC","CD","D","DC","DCC","DCCC","CM"
Tens = "","X","XX","XXX","XL","L","LX","LXX","LXXX","XC"
Ones = "","I","II","III","IV","V","VI","VII","VIII","IX"
}
$column = @{
Thousands = 0
Hundreds = 1
Tens = 2
Ones = 3
}
}
Process
{
[int[]]$digits = $Number.ToString().PadLeft(4,"0").ToCharArray() |
ForEach-Object { [Char]::GetNumericValue($_) }
$RomanNumeral = ""
$RomanNumeral += $DecimalToRoman.Thousands[$digits[$column.Thousands]]
$RomanNumeral += $DecimalToRoman.Hundreds[$digits[$column.Hundreds]]
$RomanNumeral += $DecimalToRoman.Tens[$digits[$column.Tens]]
$RomanNumeral += $DecimalToRoman.Ones[$digits[$column.Ones]]
$RomanNumeral
}
}
```
This may be (slightly) useful.
```PowerShell
1..50 | ForEach-Object {
[PSCustomObject]@{
SuperbowlNumber = $_
SuperbowlNumeral = ConvertTo-RomanNumeral -Number $_
}
}
```
```txt
SuperbowlNumber SuperbowlNumeral
--------------- ----------------
1 I
2 II
3 III
4 IV
5 V
6 VI
7 VII
8 VIII
9 IX
10 X
11 XI
12 XII
13 XIII
14 XIV
15 XV
16 XVI
17 XVII
18 XVIII
19 XIX
20 XX
21 XXI
22 XXII
23 XXIII
24 XXIV
25 XXV
26 XXVI
27 XXVII
28 XXVIII
29 XXIX
30 XXX
31 XXXI
32 XXXII
33 XXXIII
34 XXXIV
35 XXXV
36 XXXVI
37 XXXVII
38 XXXVIII
39 XXXIX
40 XL
41 XLI
42 XLII
43 XLIII
44 XLIV
45 XLV
46 XLVI
47 XLVII
48 XLVIII
49 XLIX
50 L
```
## Prolog
Library clpfd assures that the program works in both managements : Roman towards Arabic and Arabic towards Roman.
```Prolog
:- use_module(library(clpfd)).
roman :-
LA = [ _ , 2010, _, 1449, _],
LR = ['MDCCLXXXIX', _ , 'CX', _, 'MDCLXVI'],
maplist(roman, LA, LR),
maplist(my_print,LA, LR).
roman(A, R) :-
A #> 0,
roman(A, [u, t, h, th], LR, []),
label([A]),
parse_Roman(CR, LR, []),
atom_chars(R, CR).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% using DCG
roman(0, []) --> [].
roman(N, [H | T]) -->
{N1 #= N / 10,
N2 #= N mod 10},
roman(N1, T),
unity(N2, H).
unity(1, u) --> ['I'].
unity(1, t) --> ['X'].
unity(1, h) --> ['C'].
unity(1, th)--> ['M'].
unity(4, u) --> ['IV'].
unity(4, t) --> ['XL'].
unity(4, h) --> ['CD'].
unity(4, th)--> ['MMMM'].
unity(5, u) --> ['V'].
unity(5, t) --> ['L'].
unity(5, h) --> ['D'].
unity(5, th)--> ['MMMMM'].
unity(9, u) --> ['IX'].
unity(9, t) --> ['XC'].
unity(9, h) --> ['CM'].
unity(9, th)--> ['MMMMMMMMM'].
unity(0, _) --> [].
unity(V, U)-->
{V #> 5,
V1 #= V - 5},
unity(5, U),
unity(V1, U).
unity(V, U) -->
{V #> 1, V #< 4,
V1 #= V-1},
unity(1, U),
unity(V1, U).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Extraction of roman "lexeme"
parse_Roman(['C','M'|T]) -->
['CM'],
parse_Roman(T).
parse_Roman(['C','D'|T]) -->
['CD'],
parse_Roman(T).
parse_Roman(['X','C'| T]) -->
['XC'],
parse_Roman(T).
parse_Roman(['X','L'| T]) -->
['XL'],
parse_Roman(T).
parse_Roman(['I','X'| T]) -->
['IX'],
parse_Roman(T).
parse_Roman(['I','V'| T]) -->
['IV'],
parse_Roman(T).
parse_Roman([H | T]) -->
[H],
parse_Roman(T).
parse_Roman([]) -->
[].
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
my_print(A, R) :-
format('~w in roman is ~w~n', [A, R]).
```
```txt
?- roman.
1789 in roman is MDCCLXXXIX
2010 in roman is MMX
110 in roman is CX
1449 in roman is MCDXLIX
1666 in roman is MDCLXVI
true .
```
## PureBasic
```PureBasic
#SymbolCount = 12 ;0 based count
DataSection
denominations:
Data.s "M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I" ;0-12
denomValues:
Data.i 1000,900,500,400,100,90,50,40,10,9,5,4,1 ;values in decending sequential order
EndDataSection
;-setup
Structure romanNumeral
symbol.s
value.i
EndStructure
Global Dim refRomanNum.romanNumeral(#SymbolCount)
Restore denominations
For i = 0 To #SymbolCount
Read.s refRomanNum(i)\symbol
Next
Restore denomValues
For i = 0 To #SymbolCount
Read refRomanNum(i)\value
Next
Procedure.s decRoman(n)
;converts a decimal number to a roman numeral
Protected roman$, i
For i = 0 To #SymbolCount
Repeat
If n >= refRomanNum(i)\value
roman$ + refRomanNum(i)\symbol
n - refRomanNum(i)\value
Else
Break
EndIf
ForEver
Next
ProcedureReturn roman$
EndProcedure
If OpenConsole()
PrintN(decRoman(1999)) ;MCMXCIX
PrintN(decRoman(1666)) ;MDCLXVI
PrintN(decRoman(25)) ;XXV
PrintN(decRoman(954)) ;CMLIV
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit")
Input()
CloseConsole()
EndIf
```
## Python
### Imperative
# Version for Python 2
```python
roman = "MDCLXVmdclxvi"; # UPPERCASE for thousands #
adjust_roman = "CCXXmmccxxii";
arabic = (1000000, 500000, 100000, 50000, 10000, 5000, 1000, 500, 100, 50, 10, 5, 1);
adjust_arabic = (100000, 100000, 10000, 10000, 1000, 1000, 100, 100, 10, 10, 1, 1, 0);
def arabic_to_roman(dclxvi):
org = dclxvi; # 666 #
out = "";
for scale,arabic_scale in enumerate(arabic):
if org == 0: break
multiples = org / arabic_scale;
org -= arabic_scale * multiples;
out += roman[scale] * multiples;
if org >= -adjust_arabic[scale] + arabic_scale:
org -= -adjust_arabic[scale] + arabic_scale;
out += adjust_roman[scale] + roman[scale]
return out
if __name__ == "__main__":
test = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,25,30,40,50,60,69,70,
80,90,99,100,200,300,400,500,600,666,700,800,900,1000,1009,1444,1666,1945,1997,1999,
2000,2008,2500,3000,4000,4999,5000,6666,10000,50000,100000,500000,1000000);
for val in test:
print '%d - %s'%(val, arabic_to_roman(val))
```
An alternative which uses the divmod() function
```python
romanDgts= 'ivxlcdmVXLCDM_'
def ToRoman(num):
namoR = ''
if num >=4000000:
print 'Too Big -'
return '-----'
for rdix in range(0, len(romanDgts), 2):
if num==0: break
num,r = divmod(num,10)
v,r = divmod(r, 5)
if r==4:
namoR += romanDgts[rdix+1+v] + romanDgts[rdix]
else:
namoR += r*romanDgts[rdix] + (romanDgts[rdix+1] if(v==1) else '')
return namoR[-1::-1]
```
It is more Pythonic to use zip to iterate over two lists together:
```python
anums = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1]
rnums = "M CM D CD C XC L XL X IX V IV I".split()
def to_roman(x):
ret = []
for a,r in zip(anums, rnums):
n,x = divmod(x,a)
ret.append(r*n)
return ''.join(ret)
if __name__ == "__main__":
test = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,25,30,40,
50,60,69,70,80,90,99,100,200,300,400,500,600,666,700,800,900,
1000,1009,1444,1666,1945,1997,1999,2000,2008,2010,2011,2500,
3000,3999)
for val in test:
print '%d - %s'%(val, to_roman(val))
```
# Version for Python 3
```python
def arabic_to_roman(dclxvi):
#
### =====================
'''Convert an integer from the decimal notation to the Roman notation'''
org = dclxvi; # 666 #
out = "";
for scale, arabic_scale in enumerate(arabic):
if org == 0: break
multiples = org // arabic_scale;
org -= arabic_scale * multiples;
out += roman[scale] * multiples;
if (org >= -adjust_arabic[scale] + arabic_scale):
org -= -adjust_arabic[scale] + arabic_scale;
out += adjust_roman[scale] + roman[scale]
return out
if __name__ == "__main__":
test = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,25,30,40,50,60,69,70,
80,90,99,100,200,300,400,500,600,666,700,800,900,1000,1009,1444,1666,1945,1997,1999,
2000,2008,2500,3000,4000,4999,5000,6666,10000,50000,100000,500000,1000000);
for val in test:
print("%8d %s" %(val, arabic_to_roman(val)))
```
### Declarative
Less readable, but a 'one liner':
```python
rnl = [ { '4' : 'MMMM', '3' : 'MMM', '2' : 'MM', '1' : 'M', '0' : '' }, { '9' : 'CM', '8' : 'DCCC', '7' : 'DCC',
'6' : 'DC', '5' : 'D', '4' : 'CD', '3' : 'CCC', '2' : 'CC', '1' : 'C', '0' : '' }, { '9' : 'XC',
'8' : 'LXXX', '7' : 'LXX', '6' : 'LX', '5' : 'L', '4' : 'XL', '3' : 'XXX', '2' : 'XX', '1' : 'X',
'0' : '' }, { '9' : 'IX', '8' : 'VIII', '7' : 'VII', '6' : 'VI', '5' : 'V', '4' : 'IV', '3' : 'III',
'2' : 'II', '1' : 'I', '0' : '' }]
# Option 1
def number2romannumeral(n):
return ''.join([rnl[x][y] for x, y in zip(range(4), str(n).zfill(4)) if n < 5000 and n > -1])
# Option 2
def number2romannumeral(n):
return reduce(lambda x, y: x + y, map(lambda x, y: rnl[x][y], range(4), str(n).zfill(4))) if -1 < n < 5000 else None
```
Or, defining '''roman''' in terms of '''mapAccumL''':
```python
'''Encoding Roman Numerals'''
from functools import reduce
from itertools import chain
# romanFromInt :: Int -> String
def romanFromInt(n):
'''A string of Roman numerals encoding an integer.'''
def go(a, ms):
m, s = ms
q, r = divmod(a, m)
return (r, s * q)
return concat(snd(mapAccumL(go)(n)(
zip([1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1],
['M', 'CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX',
'V', 'IV', 'I'])
)))
# MAIN -------------------------------------------------
# main :: IO ()
def main():
'''Test'''
print(
list(map(romanFromInt, [1666, 1990, 2008, 2016, 2018]))
)
# GENERIC FUNCTIONS ---------------------------------------
# concat :: [[a]] -> [a]
# concat :: [String] -> String
def concat(xxs):
'''The concatenation of all the elements in a list.'''
xs = list(chain.from_iterable(xxs))
unit = '' if isinstance(xs, str) else []
return unit if not xs else (
''.join(xs) if isinstance(xs[0], str) else xs
)
# mapAccumL :: (acc -> x -> (acc, y)) -> acc -> [x] -> (acc, [y])
def mapAccumL(f):
'''A tuple of an accumulation and a list derived by a
combined map and fold,
with accumulation from left to right.'''
def go(a, x):
tpl = f(a[0], x)
return (tpl[0], a[1] + [tpl[1]])
return lambda acc: lambda xs: (
reduce(go, xs, (acc, []))
)
# snd :: (a, b) -> b
def snd(tpl):
'''Second component of a tuple.'''
return tpl[1]
# MAIN ---
if __name__ == '__main__':
main()
```
```txt
['MDCLXVI', 'MCMXC', 'MMVIII', 'MMXVI', 'MMXVIII']
```
## R
R has a built-in function, [https://svn.r-project.org/R/trunk/src/library/utils/R/roman.R as.roman], for conversion to Roman numerals. The implementation details are found in utils:::.numeric2roman (see previous link), and utils:::.roman2numeric, for conversion back to Arabic decimals.
```R
as.roman(1666) # MDCLXVI
```
Since the object as.roman creates is just an integer vector with a class, you can do arithmetic with Roman numerals:
```R
as.roman(1666) + 334 # MM
```
## Racket
Straight recursion:
```Racket
#lang racket
(define (encode/roman number)
(cond ((>= number 1000) (string-append "M" (encode/roman (- number 1000))))
((>= number 900) (string-append "CM" (encode/roman (- number 900))))
((>= number 500) (string-append "D" (encode/roman (- number 500))))
((>= number 400) (string-append "CD" (encode/roman (- number 400))))
((>= number 100) (string-append "C" (encode/roman (- number 100))))
((>= number 90) (string-append "XC" (encode/roman (- number 90))))
((>= number 50) (string-append "L" (encode/roman (- number 50))))
((>= number 40) (string-append "XL" (encode/roman (- number 40))))
((>= number 10) (string-append "X" (encode/roman (- number 10))))
((>= number 9) (string-append "IX" (encode/roman (- number 9))))
((>= number 5) (string-append "V" (encode/roman (- number 5))))
((>= number 4) (string-append "IV" (encode/roman (- number 4))))
((>= number 1) (string-append "I" (encode/roman (- number 1))))
(else "")))
```
Using for/fold and quotient/remainder to remove repetition:
```Racket
#lang racket
(define (number->list n)
(for/fold ([result null])
([decimal '(1000 900 500 400 100 90 50 40 10 9 5 4 1)]
[roman '(M CM D CD C XC L XL X IX V IV I)])
#:break (= n 0)
(let-values ([(q r) (quotient/remainder n decimal)])
(set! n r)
(append result (make-list q roman)))))
(define (encode/roman number)
(string-join (map symbol->string (number->list number)) ""))
(for ([n '(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 25 30 40
50 60 69 70 80 90 99 100 200 300 400 500 600 666 700 800 900
1000 1009 1444 1666 1945 1997 1999 2000 2008 2010 2011 2500
3000 3999)])
(printf "~a ~a\n" n (encode/roman n)))
```
## Red
Straight iterative solution:
```Red
table: [1000 M 900 CM 500 D 400 CD 100 C 90 XC 50 L 40 XL 10 X 5 V 4 IV 1 I]
to-Roman: function [n [integer!] return: [string!]][
out: copy ""
foreach [a r] table [while [n >= a][append out r n: n - a]]
out
]
foreach number [40 33 1888 2016][print [number ":" to-Roman number]]
```
Straight recursive solution:
```Red
table: [1000 M 900 CM 500 D 400 CD 100 C 90 XC 50 L 40 XL 10 X 5 V 4 IV 1 I]
to-Roman: func [n [integer!] return: [string!]][
case [
tail? table [table: head table copy ""]
table/1 > n [table: skip table 2 to-Roman n]
'else [append copy form table/2 to-Roman n - table/1]
]
]
foreach number [40 33 1888 2016][print [number ":" to-Roman number]]
```
This solution builds, using metaprogramming, a `case` table, that relies on recursion to convert every digit.
```Red
to-Roman: function [n [integer!]] reduce [
'case collect [
foreach [a r] [1000 M 900 CM 500 D 400 CD 100 C 90 XC 50 L 40 XL 10 X 9 IX 5 V 4 IV 1 I][
keep compose/deep [n >= (a) [append copy (form r) any [to-Roman n - (a) copy ""]]]
]
]
]
foreach number [40 33 1888 2016][print [number ":" to-Roman number]]
```
## Retro
This is a port of the [[Forth]] code; but returns a string rather than displaying the roman numerals. It only handles numbers between 1 and 3999.
```Retro
: vector ( ...n"- )
here [ &, times ] dip : .data ` swap ` + ` @ ` do ` ; ;
: .I dup @ ^buffer'add ;
: .V dup 1 + @ ^buffer'add ;
: .X dup 2 + @ ^buffer'add ;
[ .I .X drop ]
[ .V .I .I .I drop ]
[ .V .I .I drop ]
[ .V .I drop ]
[ .V drop ]
[ .I .V drop ]
[ .I .I .I drop ]
[ .I .I drop ]
[ .I drop ]
&drop
10 vector .digit
: record ( an- )
10 /mod dup [ [ over 2 + ] dip record ] &drop if .digit ;
: toRoman ( n-a )
here ^buffer'set
dup 1 3999 within 0 =
[ "EX LIMITO!\n" ] [ "IVXLCDM" swap record here ] if ;
```
## REXX
### version 1
```rexx
roman: procedure
arg number
/* handle only 1 to 3999, else return ? */
if number >= 4000 | number <= 0 then return "?"
romans = " M CM D CD C XC L XL X IX V IV I"
arabic = "1000 900 500 400 100 90 50 40 10 9 5 4 1"
result = ""
do i = 1 to words(romans)
do while number >= word(arabic,i)
result = result || word(romans,i)
number = number - word(arabic,i)
end
end
return result
```
### version 2
This version of a REXX program allows almost any non-negative decimal integer.
Most people think that the Romans had no word for "zero". The Roman numeral system has no need for a
zero ''placeholder'', so there was no name for it (just as we have no name for a "¶" in the middle of our
numbers ─── as we don't have that possibility). However, the Romans did have a name for zero (or nothing).
In fact the Romans had several names for zero (see the REXX code), as does modern English. In American
English, many words can be used for '''0''': zero, nothing, naught, bupkis, zilch, goose-egg, nebbish, squat, nil,
crapola, what-Patty-shot-at, nineteen (only in cribbage), love (in tennis), etc.
Also, this REXX version supports large numbers (with parentheses and deep parentheses).
(This REXX code was ripped out of my general routine that also supported versions for '''Attic''', '''ancient Roman''',
and '''modern Roman''' numerals.)
The general REXX code is bulkier than most at it deals with ''any'' non-negative decimal number, and more
boilerplate code is in the general REXX code to handle the above versions.
```rexx
/*REXX program converts (Arabic) non─negative decimal integers (≥0) ───► Roman numerals.*/
numeric digits 10000 /*decimal digs can be higher if wanted.*/
parse arg # /*obtain optional integers from the CL.*/
@er= "argument isn't a non-negative integer: " /*literal used when issuing error msg. */
if #='' then /*Nothing specified? Then generate #s.*/
do
do j= 0 by 11 to 111; #=# j; end
#=# 49; do k=88 by 100 to 1200; #=# k; end
#=# 1000 2000 3000 4000 5000 6000; do m=88 by 200 to 1200; #=# m; end
#=# 1304 1405 1506 1607 1708 1809 1910 2011; do p= 4 to 50; #=# 10**p; end
end /*finished with generation of numbers. */
do i=1 for words(#); x=word(#, i) /*convert each of the numbers───►Roman.*/
if \datatype(x, 'W') | x<0 then say "***error***" @er x /*¬ whole #? negative?*/
say right(x, 55) dec2rom(x)
end /*i*/
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
dec2rom: procedure; parse arg n,# /*obtain the number, assign # to a null*/
n=space(translate(n/1, , ','), 0) /*remove commas from normalized integer*/
nulla= 'ZEPHIRUM NULLAE NULLA NIHIL' /*Roman words for "nothing" or "none". */
if n==0 then return word(nulla, 1) /*return a Roman word for "zero". */
maxnp=(length(n)-1)%3 /*find max(+1) # of parenthesis to use.*/
highPos=(maxnp+1)*3 /*highest position of number. */
nn=reverse( right(n, highPos, 0) ) /*digits for Arabic──►Roman conversion.*/
do j=highPos to 1 by -3
_=substr(nn, j, 1); select /*════════════════════hundreds.*/
when _==9 then hx='CM'
when _>=5 then hx='D'copies("C", _-5)
when _==4 then hx='CD'
otherwise hx= copies('C', _)
end /*select hundreds*/
_=substr(nn, j-1, 1); select /*════════════════════════tens.*/
when _==9 then tx='XC'
when _>=5 then tx='L'copies("X", _-5)
when _==4 then tx='XL'
otherwise tx= copies('X', _)
end /*select tens*/
_=substr(nn, j-2, 1); select /*═══════════════════════units.*/
when _==9 then ux='IX'
when _>=5 then ux='V'copies("I", _-5)
when _==4 then ux='IV'
otherwise ux= copies('I', _)
end /*select units*/
$=hx || tx || ux
if $\=='' then #=# || copies("(", (j-1)%3)$ ||copies(')', (j-1)%3)
end /*j*/
if pos('(I',#)\==0 then do i=1 for 4 /*special case: M,MM,MMM,MMMM.*/
if i==4 then _ = '(IV)'
else _ = '('copies("I", i)')'
if pos(_, #)\==0 then #=changestr(_, #, copies('M', i))
end /*i*/
return #
```
Some older REXXes don't have a '''changestr''' BIF, so one is included here ──► [[CHANGESTR.REX]].
'''output''' when using the default (internal) input):
0 ZEPHIRUM
11 XI
22 XXII
33 XXXIII
44 XLIV
55 LV
66 LXVI
77 LXXVII
88 LXXXVIII
99 XCIX
110 CX
49 XLIX
88 LXXXVIII
188 CLXXXVIII
288 CCLXXXVIII
388 CCCLXXXVIII
488 CDLXXXVIII
588 DLXXXVIII
688 DCLXXXVIII
788 DCCLXXXVIII
888 DCCCLXXXVIII
988 CMLXXXVIII
1088 MLXXXVIII
1188 MCLXXXVIII
1000 M
2000 MM
3000 MMM
4000 MMMM
5000 (V)
6000 (VI)
88 LXXXVIII
288 CCLXXXVIII
488 CDLXXXVIII
688 DCLXXXVIII
888 DCCCLXXXVIII
1088 MLXXXVIII
1304 MCCCIV
1405 MCDV
1506 MDVI
1607 MDCVII
1708 MDCCVIII
1809 MDCCCIX
1910 MCMX
2011 MMXI
10000 (X)
100000 (C)
1000000 (M)
10000000 ((X))
100000000 ((C))
1000000000 ((M))
10000000000 (((X)))
100000000000 (((C)))
1000000000000 (((M)))
10000000000000 ((((X))))
100000000000000 ((((C))))
1000000000000000 ((((M))))
10000000000000000 (((((X)))))
100000000000000000 (((((C)))))
1000000000000000000 (((((M)))))
10000000000000000000 ((((((X))))))
100000000000000000000 ((((((C))))))
1000000000000000000000 ((((((M))))))
10000000000000000000000 (((((((X)))))))
100000000000000000000000 (((((((C)))))))
1000000000000000000000000 (((((((M)))))))
10000000000000000000000000 ((((((((X))))))))
100000000000000000000000000 ((((((((C))))))))
1000000000000000000000000000 ((((((((M))))))))
10000000000000000000000000000 (((((((((X)))))))))
100000000000000000000000000000 (((((((((C)))))))))
1000000000000000000000000000000 (((((((((M)))))))))
10000000000000000000000000000000 ((((((((((X))))))))))
100000000000000000000000000000000 ((((((((((C))))))))))
1000000000000000000000000000000000 ((((((((((M))))))))))
10000000000000000000000000000000000 (((((((((((X)))))))))))
100000000000000000000000000000000000 (((((((((((C)))))))))))
1000000000000000000000000000000000000 (((((((((((M)))))))))))
10000000000000000000000000000000000000 ((((((((((((X))))))))))))
100000000000000000000000000000000000000 ((((((((((((C))))))))))))
1000000000000000000000000000000000000000 ((((((((((((M))))))))))))
10000000000000000000000000000000000000000 (((((((((((((X)))))))))))))
100000000000000000000000000000000000000000 (((((((((((((C)))))))))))))
1000000000000000000000000000000000000000000 (((((((((((((M)))))))))))))
10000000000000000000000000000000000000000000 ((((((((((((((X))))))))))))))
100000000000000000000000000000000000000000000 ((((((((((((((C))))))))))))))
1000000000000000000000000000000000000000000000 ((((((((((((((M))))))))))))))
10000000000000000000000000000000000000000000000 (((((((((((((((X)))))))))))))))
100000000000000000000000000000000000000000000000 (((((((((((((((C)))))))))))))))
1000000000000000000000000000000000000000000000000 (((((((((((((((M)))))))))))))))
10000000000000000000000000000000000000000000000000 ((((((((((((((((X))))))))))))))))
100000000000000000000000000000000000000000000000000 ((((((((((((((((C))))))))))))))))
```
## Ring
```ring
arabic = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1]
roman = ["M", "CM", "D", "CD", "C" ,"XC", "L", "XL" ,"X", "IX", "V", "IV", "I"]
see "2009 = " + toRoman(2009) + nl
see "1666 = " + toRoman(1666) + nl
see "3888 = " + toRoman(3888) + nl
func toRoman val
result = ""
for i = 1 to 13
while val >= arabic[i]
result = result + roman[i]
val = val - arabic[i]
end
next
return result
```
## Ruby
Roman numeral generation was used as an example for demonstrating [http://www.xpsd.org/cgi-bin/wiki?TestDrivenDevelopmentTutorialRomanNumerals Test Driven Development] in Ruby. The solution came to be:
```ruby
Symbols = { 1=>'I', 5=>'V', 10=>'X', 50=>'L', 100=>'C', 500=>'D', 1000=>'M' }
Subtractors = [ [1000, 100], [500, 100], [100, 10], [50, 10], [10, 1], [5, 1], [1, 0] ]
def roman(num)
return Symbols[num] if Symbols.has_key?(num)
Subtractors.each do |cutPoint, subtractor|
return roman(cutPoint) + roman(num - cutPoint) if num > cutPoint
return roman(subtractor) + roman(num + subtractor) if num >= cutPoint - subtractor and num < cutPoint
end
end
[1990, 2008, 1666].each do |i|
puts "%4d => %s" % [i, roman(i)]
end
```
```txt
1990 => MCMXC
2008 => MMVIII
1666 => MDCLXVI
```
Another shorter version if we don't consider calculating the substractors:
```ruby
Symbols = [ [1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50, 'L'], [40, 'XL'], [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I'] ]
def arabic_to_roman(arabic)
return '' if arabic.zero?
Symbols.each { |arabic_rep, roman_rep| return roman_rep + arabic_to_roman(arabic - arabic_rep) if arabic >= arabic_rep }
end
```
Yet another way to solve it in terms of reduce
```ruby
Symbols = [ [1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50, 'L'], [40, 'XL'], [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I'] ]
def to_roman(num)
Symbols.reduce "" do |memo, (divisor, letter)|
div, num = num.divmod(divisor)
memo + letter * div
end
end
```
## Run BASIC
```runbasic
[loop]
input "Input value:";val$
print roman$(val$)
goto [loop]
' ------------------------------
' Roman numerals
' ------------------------------
FUNCTION roman$(val$)
a2r$ = "M:1000,CM:900,D:500,CD:400,C:100,XC:90,L:50,XL:40,X:10,IX:9,V:5,IV:4,I:1"
v = val(val$)
for i = 1 to 13
r$ = word$(a2r$,i,",")
a = val(word$(r$,2,":"))
while v >= a
roman$ = roman$ + word$(r$,1,":")
v = v - a
wend
next i
END FUNCTION
```
## Rust
```rust
struct RomanNumeral {
symbol: &'static str,
value: u32
}
const NUMERALS: [RomanNumeral; 13] = [
RomanNumeral {symbol: "M", value: 1000},
RomanNumeral {symbol: "CM", value: 900},
RomanNumeral {symbol: "D", value: 500},
RomanNumeral {symbol: "CD", value: 400},
RomanNumeral {symbol: "C", value: 100},
RomanNumeral {symbol: "XC", value: 90},
RomanNumeral {symbol: "L", value: 50},
RomanNumeral {symbol: "XL", value: 40},
RomanNumeral {symbol: "X", value: 10},
RomanNumeral {symbol: "IX", value: 9},
RomanNumeral {symbol: "V", value: 5},
RomanNumeral {symbol: "IV", value: 4},
RomanNumeral {symbol: "I", value: 1}
];
fn to_roman(mut number: u32) -> String {
let mut min_numeral = String::new();
for numeral in NUMERALS.iter() {
while numeral.value <= number {
min_numeral = min_numeral + numeral.symbol;
number -= numeral.value;
}
}
min_numeral
}
fn main() {
let nums = [2014, 1999, 25, 1666, 3888];
for &n in nums.iter() {
// 4 is minimum printing width, for alignment
println!("{:2$} = {}", n, to_roman(n), 4);
}
}
```
```txt
2014 = MMXIV
1999 = MCMXCIX
25 = XXV
1666 = MDCLXVI
3888 = MMMDCCCLXXXVIII
```
## Scala
```scala
val romanDigits = Map(
1 -> "I", 5 -> "V",
10 -> "X", 50 -> "L",
100 -> "C", 500 -> "D",
1000 -> "M",
4 -> "IV", 9 -> "IX",
40 -> "XL", 90 -> "XC",
400 -> "CD", 900 -> "CM")
val romanDigitsKeys = romanDigits.keysIterator.toList sortBy (x => -x)
def toRoman(n: Int): String = romanDigitsKeys find (_ >= n) match {
case Some(key) => romanDigits(key) + toRoman(n - key)
case None => ""
}
```
```txt
scala> List(1990, 2008, 1666) map toRoman
res55: List[String] = List(MCMXC, MMVIII, MDCLXVI)
```
### Using foldLeft
```Scala
def toRoman( v:Int ) : String = {
val romanNumerals = List(1000->"M",900->"CM",500->"D",400->"CD",100->"C",90->"XC",
50->"L",40->"XL",10->"X",9->"IX",5->"V",4->"IV",1->"I")
var n = v
romanNumerals.foldLeft(""){(s,t) => {val c = n/t._1; n = n-t._1*c; s + (t._2 * c) } }
}
// A small test
def test( arabic:Int ) = println( arabic + " => " + toRoman( arabic ) )
test(1990)
test(2008)
test(1666)
```
===Different code-style===
```Scala
def toRoman(num: Int): String = {
case class RomanUnit(value: Int, token: String)
val romanNumerals = List(
RomanUnit(1000, "M"),
RomanUnit(900, "CM"),
RomanUnit(500, "D"),
RomanUnit(400, "CD"),
RomanUnit(100, "C"),
RomanUnit(90, "XC"),
RomanUnit(50, "L"),
RomanUnit(40, "XL"),
RomanUnit(10, "X"),
RomanUnit(9, "IX"),
RomanUnit(5, "V"),
RomanUnit(4, "IV"),
RomanUnit(1, "I"))
var remainingNumber = num
romanNumerals.foldLeft("") { (outputStr, romanUnit) =>
{
val times = remainingNumber / romanUnit.value
remainingNumber -= romanUnit.value * times
outputStr + (romanUnit.token * times)
}
}
}
```
```txt
1990 => MCMXC
2008 => MMVIII
1666 => MDCLXVI
```
## Scheme
This uses format directives supported in Chez Scheme since v6.9b; YMMV.
```scheme
(define (to-roman n)
(format "~@r" n))
```
This is a general example using Chicken Scheme.
```scheme
(define roman-decimal
'(("M" . 1000)
("CM" . 900)
("D" . 500)
("CD" . 400)
("C" . 100)
("XC" . 90)
("L" . 50)
("XL" . 40)
("X" . 10)
("IX" . 9)
("V" . 5)
("IV" . 4)
("I" . 1)))
(define (to-roman value)
(apply string-append
(let loop ((v value)
(decode roman-decimal))
(let ((r (caar decode))
(d (cdar decode)))
(cond
((= v 0) '())
((>= v d) (cons r (loop (- v d) decode)))
(else (loop v (cdr decode))))))))
(let loop ((n '(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 25 30 40
50 60 69 70 80 90 99 100 200 300 400 500 600 666 700 800 900
1000 1009 1444 1666 1945 1997 1999 2000 2008 2010 2011 2500
3000 3999)))
(unless (null? n)
(printf "~a ~a\n" (car n) (to-roman (car n)))
(loop (cdr n))))
```
## Seed7
The following program writes the numbers between 1 and 3999 as roman numerals.
The [http://seed7.sourceforge.net/libraries/wrinum.htm wrinum.s7i] library contains the
function [http://seed7.sourceforge.net/libraries/wrinum.htm#str%28ROMAN,in_integer%29 str(ROMAN,)],
which writes a roman numeral to a string.
```seed7
$ include "seed7_05.s7i";
include "stdio.s7i";
include "wrinum.s7i";
const proc: main is func
local
var integer: number is 0;
begin
for number range 1 to 3999 do
writeln(str(ROMAN, number));
end for;
end func;
```
Original source [http://seed7.sourceforge.net/algorith/puzzles.htm#roman_numerals].
## SETL
```ada
examples := [2008, 1666, 1990];
for example in examples loop
print( roman_numeral(example) );
end loop;
proc roman_numeral( n );
R := [[1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50, 'L'], [40, 'XL'], [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I']];
roman := '';
for numeral in R loop
while n >= numeral(1) loop
n := n - numeral(1);
roman := roman + numeral(2);
end loop;
end loop;
return roman;
end;
```
```txt
MMVIII
MDCLXVI
MCMXC
```
## Sidef
```ruby
func arabic2roman(num, roman='') {
static lookup = [
:M:1000, :CM:900, :D:500,
:CD:400, :C:100, :XC:90,
:L:50, :XL:40, :X:10,
:IX:9, :V:5, :IV:4,
:I:1
];
lookup.each { |pair|
while (num >= pair.second) {
roman += pair.first;
num -= pair.second;
}
}
return roman;
}
say("1990 in roman is " + arabic2roman(1990));
say("2008 in roman is " + arabic2roman(2008));
say("1666 in roman is " + arabic2roman(1666));
```
```txt
1990 in roman is MCMXC
2008 in roman is MMVIII
1666 in roman is MDCLXVI
```
## Simula
```simula
BEGIN
TEXT PROCEDURE TOROMAN(N); INTEGER N;
BEGIN
PROCEDURE P(WEIGHT,LIT); INTEGER WEIGHT; TEXT LIT;
BEGIN
WHILE N >= WEIGHT DO
BEGIN
T :- T & LIT;
N := N - WEIGHT;
END WHILE;
END P;
TEXT T; T :- NOTEXT;
P( 1000, "M" );
P( 900, "CM" );
P( 500, "D" );
P( 400, "CD" );
P( 100, "C" );
P( 90, "XC" );
P( 50, "L" );
P( 40, "XL" );
P( 10, "X" );
P( 9, "IX" );
P( 5, "V" );
P( 4, "IV" );
P( 1, "I" );
TOROMAN :- T;
END TOROMAN;
INTEGER Y;
FOR Y := 1990, 2008, 1666 DO
BEGIN
OUTTEXT("YEAR ");
OUTINT(Y, 4);
OUTTEXT(" => ");
OUTTEXT(TOROMAN(Y));
OUTIMAGE;
END FOR;
END PROGRAM;
```
```txt
YEAR 1990 => MCMXC
YEAR 2008 => MMVIII
YEAR 1666 => MDCLXVI
```
## Smalltalk
in ST/X, integers already know how to print themselves as roman number:
```smalltalk>2013 printRomanOn:Stdout naive:false 0 ifFalse:[self error:'negative roman'].
naive ifTrue:[
spec := #(
" value string repeat "
1000 'M' true
500 'D' false
100 'C' true
50 'L' false
10 'X' true
5 'V' false
1 'I' true
).
] ifFalse:[
spec := #(
" value string repeat "
1000 'M' true
900 'CM' false
500 'D' false
400 'CD' false
100 'C' true
90 'XC' false
50 'L' false
40 'XL' false
10 'X' true
9 'IX' false
5 'V' false
4 'IV' false
1 'I' true
).
].
spec
inGroupsOf:3
do:[:rValue :rString :repeatFlag |
[
(restValue >= rValue) ifTrue:[
aStream nextPutAll:rString.
restValue := restValue - rValue.
].
] doWhile:[ repeatFlag and:[ restValue >= rValue] ].
].
```
## SNOBOL4
Adapted from [http://burks.bton.ac.uk/burks/language/snobol/catspaw/tutorial/ch6.htm Catspaw SNOBOL Tutorial, Chapter 6]
```snobol4
* ROMAN(N) - Convert integer N to Roman numeral form.
*
* N must be positive and less than 4000.
*
* An asterisk appears in the result if N >= 4000.
*
* The function fails if N is not an integer.
DEFINE('ROMAN(N)UNITS') :(ROMAN_END)
* Get rightmost digit to UNITS and remove it from N.
* Return null result if argument is null.
ROMAN N RPOS(1) LEN(1) . UNITS = :F(RETURN)
* Search for digit, replace with its Roman form.
* Return failing if not a digit.
'0,1I,2II,3III,4IV,5V,6VI,7VII,8VIII,9IX,' UNITS
+ BREAK(',') . UNITS :F(FRETURN)
* Convert rest of N and multiply by 10. Propagate a
* failure return from recursive call back to caller.
ROMAN = REPLACE(ROMAN(N), 'IVXLCDM', 'XLCDM**')
+ UNITS :S(RETURN) F(FRETURN)
ROMAN_END
* Testing
OUTPUT = "1999 = " ROMAN(1999)
OUTPUT = " 24 = " ROMAN(24)
OUTPUT = " 944 = " ROMAN(944)
END
```
```txt
1999 = MCMXCIX
24 = XXIV
944 = CMXLIV
```
Here's a non-recursive version, and a Roman-to-Arabic converter to boot.
```SNOBOL4
* # Arabic to Roman
define('roman(n)s,ch,val,str') :(roman_end)
roman roman = ge(n,4000) n :s(return)
s = 'M1000 CM900 D500 CD400 C100 XC90 L50 XL40 X10 IX9 V5 IV4 I1 '
rom1 s span(&ucase) . ch break(' ') . val span(' ') = :f(rom2)
str = str dupl(ch,(n / val))
n = remdr(n,val) :(rom1)
rom2 roman = str :(return)
roman_end
* # Roman to Arabic
define('arabic(n)s,ch,val,sum,x') :(arabic_end)
arabic s = 'M1000 D500 C100 L50 X10 V5 I1 '
n = reverse(n)
arab1 n len(1) . ch = :f(arab2)
s ch break(' ') . val
val = lt(val,x) (-1 * val)
sum = sum + val; x = val :(arab1)
arab2 arabic = sum :(return)
arabic_end
* # Test and display
tstr = '2010 1999 1492 1066 476 '
tloop tstr break(' ') . year span(' ') = :f(out)
r = roman(year)
rstr = rstr year '=' r ' '
astr = astr r '=' arabic(r) ' ' :(tloop)
out output = rstr; output = astr
end
```
```txt
2010=MMX 1999=MCMXCIX 1492=MCDXCII 1066=MLXVI 476=CDLXXVI
MMX=2010 MCMXCIX=1999 MCDXCII=1492 MLXVI=1066 CDLXXVI=476
```
## SPL
```spl
a2r(a)=
r = ""
n = [["M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"],[1000,900,500,400,100,90,50,40,10,9,5,4,1]]
> i, 1..13
> a! i, 1..#.size(t,1)
#.output(t[i]," = ",a2r(t[i]))
<
```
```txt
1990 = MCMXC
2008 = MMVIII
1666 = MDCLXVI
```
## SQL
```SQL
--
-- This only works under Oracle and has the limitation of 1 to 3999
SQL> select to_char(1666, 'RN') urcoman, to_char(1666, 'rn') lcroman from dual;
URCOMAN LCROMAN
--------------- ---------------
MDCLXVI mdclxvi
```
## Swift
```swift
func ator(var n: Int) -> String {
var result = ""
for (value, letter) in
[( 1000, "M"),
( 900, "CM"),
( 500, "D"),
( 400, "CD"),
( 100, "C"),
( 90, "XC"),
( 50, "L"),
( 40, "XL"),
( 10, "X"),
( 9, "IX"),
( 5, "V"),
( 4, "IV"),
( 1, "I")]
{
while n >= value {
result += letter
n -= value
}
}
return result
}
```
Sample call:
```swift
println(ator(1666)) // MDCLXVI
```
```swift
print(ator(1666)) // MDCLXVI
```
```txt
MDCLXVI
```
## Tcl
```tcl
proc to_roman {i} {
set map {1000 M 900 CM 500 D 400 CD 100 C 90 XC 50 L 40 XL 10 X 9 IX 5 V 4 IV 1 I}
foreach {value roman} $map {
while {$i >= $value} {
append res $roman
incr i -$value
}
}
return $res
}
```
=={{header|TI-83 BASIC}}==
```ti83b
PROGRAM:DEC2ROM
:"="→Str1
:Lbl ST
:ClrHome
:Disp "NUMBER TO"
:Disp "CONVERT:"
:Input A
:If fPart(A) or A≠abs(A)
:Then
:Goto PI
:End
:A→B
:While B≥1000
:Str1+"M"→Str1
:B-1000→B
:End
:If B≥900
:Then
:Str1+"CM"→Str1
:B-900→B
:End
:If B≥500
:Then
:Str1+"D"→Str1
:B-500→B
:End
:If B≥400
:Then
:Str1+"CD"?Str1
:B-400→B
:End
:While B≥100
:Str1+"C"→Str1
:B-100→B
:End
:If B≥90
:Then
:Str1+"XC"→Str1
:B-90→B
:End
:If B≥50
:Then
:Str1+"L"→Str1
:B-50→B
:End
:If B≥40
:Then
:Str1+"XL"→Str1
:B-40→B
:End
:While B≥10
:Str1+"X"→Str1
:B-10→B
:End
:If B≥9
:Then
:Str1+"IX"→Str1
:B-9→B
:End
:If B≥5
:Then
:Str1+"V"→Str1
:B-5→B
:End
:If B≥4
:Then
:Str1+"IV"→Str1
:B-4→B
:End
:While B>0
:Str1+"I"→Str1
:B-1→B
:End
:ClrHome
:Disp A
:Disp Str1
:Stop
:Lbl PI
:ClrHome
:Disp "THE NUMBER MUST"
:Disp "BE A POSITIVE"
:Disp "INTEGER."
:Pause
:Goto ST
```
## TUSCRIPT
```tuscript
$$ MODE TUSCRIPT
LOOP arab_number="1990'2008'1666"
roman_number = ENCODE (arab_number,ROMAN)
PRINT "Arabic number ",arab_number, " equals ", roman_number
ENDLOOP
```
```txt
Arabic number 1990 equals MCMXC
Arabic number 2008 equals MMVIII
Arabic number 1666 equals MDCLXVI
```
## uBasic/4tH
Push 1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900, 1000
' Initialize array
For i = 12 To 0 Step -1
@(i) = Pop()
Next
' Calculate and print numbers
Print 1999, : Proc _FNroman (1999)
Print 2014, : Proc _FNroman (2014)
Print 1666, : Proc _FNroman (1666)
Print 3888, : Proc _FNroman (3888)
End
_FNroman Param (1) ' ( n --)
Local (1) ' Define b@
' Try all numbers in array
For b@ = 12 To 0 Step -1
Do While a@ > @(b@) - 1 ' Several occurences of same number?
GoSub ((b@ + 1) * 10) ' Print roman digit
a@ = a@ - @(b@) ' Decrement number
Loop
Next
Print ' Terminate line
Return
' Print roman digits
10 Print "I"; : Return
20 Print "IV"; : Return
30 Print "V"; : Return
40 Print "IX"; : Return
50 Print "X"; : Return
60 Print "XL"; : Return
70 Print "L"; : Return
80 Print "XC"; : Return
90 Print "C"; : Return
100 Print "CD"; : Return
110 Print "D"; : Return
120 Print "CM"; : Return
130 Print "M"; : Return
```
## UNIX Shell
```bash
roman() {
local values=( 1000 900 500 400 100 90 50 40 10 5 4 1 )
local roman=(
[1000]=M [900]=CM [500]=D [400]=CD
[100]=C [90]=XC [50]=L [40]=XL
[10]=X [9]=IX [5]=V [4]=IV
[1]=I
)
local nvmber=""
local num=$1
for value in ${values[@]}; do
while (( num >= value )); do
nvmber+=${roman[value]}
((num -= value))
done
done
echo $nvmber
}
for test in 1999 24 944 1666 2008; do
printf "%d = %s\n" $test $(roman $test)
done
```
```txt
1999 = MCMXCVIV
24 = XXIV
944 = CMXLIV
1666 = MDCLXVI
2008 = MMVIII
```
## Ursala
The algorithm is to implement the
[http://www.en.wikipedia.org/wiki/Roman_Numerals#Subtractive_principle subtractive principle]
by string substitution only after constucting the numeral from successive
remainders. The order among the substitutions matters. For example,
occurrences of DCCCC must be replaced by CM before any occurrences of
CCCC are replaced by CD. The substitution operator (%=) is helpful
here.
```Ursala
#import nat
roman =
-+
'IIII'%='IV'+ 'VIIII'%='IX'+ 'XXXX'%='XL'+ 'LXXXX'%='XC'+ 'CCCC'%='CD'+ 'DCCCC'%='CM',
~&plrDlSPSL/'MDCLXVI'+ iota*+ +^|(^|C/~&,\/division)@rlX=>~&iNC <1000,500,100,50,10,5>+-
```
This test program applies the function to each member of a list of numbers.
```Ursala
#show+
test = roman* <1990,2008,1,2,64,124,1666,10001>
```
```txt
MCMXC
MMVIII
I
II
LXIV
CXXIV
MDCLXVI
MMMMMMMMMMI
```
## Vedit macro language
```vedit
// Main program for testing the function
//
do {
#1 = Get_Num("Number to convert: ", STATLINE)
Call("NUM_TO_ROMAN")
Num_Type(#1, NOCR) Message(" = ") Reg_Type(1) Type_Newline
} while (Reg_Size(1))
Return
// Convert numeric value into Roman number
// #1 = number to convert; on return: T-reg(1) = Roman number
//
:NUM_TO_ROMAN:
Reg_Empty(1) // @1 = Results (Roman number)
if (#1 < 1) { Return } // non-positive numbers return empty string
Buf_Switch(Buf_Free)
Ins_Text("M1000,CM900,D500,CD400,C100,XC90,L50,XL40,X10,IX9,V5,IV4,I1")
BOF
#2 = #1
Repeat(ALL) {
Search("|A|[|A]", ADVANCE+ERRBREAK) // get next item from conversion list
Reg_Copy_Block(20, CP-Chars_Matched, CP) // @20 = Letter(s) to be inserted
#11 = Num_Eval() // #11 = magnitude (1000...1)
while (#2 >= #11) {
Reg_Set(1, @20, APPEND)
#2 -= #11
}
}
Buf_Quit(OK)
Return
```
```txt
4 = IV
12 = XII
1666 = MDCLXVI
1990 = MCMXC
2011 = MMXI
```
## Visual Basic
```vb
Function toRoman(value) As String
Dim arabic As Variant
Dim roman As Variant
arabic = Array(1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1)
roman = Array("M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I")
Dim i As Integer, result As String
For i = 0 To 12
Do While value >= arabic(i)
result = result + roman(i)
value = value - arabic(i)
Loop
Next i
toRoman = result
End Function
Sub Main()
MsgBox toRoman(Val(InputBox("Number, please")))
End Sub
```
## XBasic
```xbasic
PROGRAM "romanenc"
VERSION "0.0000"
DECLARE FUNCTION Entry()
INTERNAL FUNCTION ToRoman$(aValue%%)
' 3888 or MMMDCCCLXXXVIII (15 chars) is the longest string properly encoded with these symbols.
FUNCTION Entry()
PRINT ToRoman$(1990) ' MCMXC
PRINT ToRoman$(2018) ' MMXVIII
PRINT ToRoman$(3888) ' MMMDCCCLXXXVIII
END FUNCTION
FUNCTION ToRoman$(aValue%%)
DIM weights%%[12]
DIM symbols$[12]
weights%%[0] = 1000
weights%%[1] = 900
weights%%[2] = 500
weights%%[3] = 400
weights%%[4] = 100
weights%%[5] = 90
weights%%[6] = 50
weights%%[7] = 40
weights%%[8] = 10
weights%%[9] = 9
weights%%[10] = 5
weights%%[11] = 4
weights%%[12] = 1
symbols$[0] = "M"
symbols$[1] = "CM"
symbols$[2] = "D"
symbols$[3] = "CD"
symbols$[4] = "C"
symbols$[5] = "XC"
symbols$[6] = "L"
symbols$[7] = "XL"
symbols$[8] = "X"
symbols$[9] = "IX"
symbols$[10] = "V"
symbols$[11] = "IV"
symbols$[12] = "I"
destination$ = ""
i@@ = 0
DO WHILE (i@@ <= 12) AND (aValue%% > 0)
DO WHILE aValue%% >= weights%%[i@@]
destination$ = destination$ + symbols$[i@@]
aValue%% = aValue%% - weights%%[i@@]
LOOP
i@@ = i@@ + 1
LOOP
RETURN destination$
END FUNCTION
END PROGRAM
```
```txt
MCMXC
MMXVIII
MMMDCCCLXXXVIII
```
## XLISP
```lisp
(defun roman (n)
(define roman-numerals '((1000 "m") (900 "cm") (500 "d") (400 "cd") (100 "c") (90 "xc") (50 "l") (40 "xl") (10 "x") (9 "ix") (5 "v") (4 "iv") (1 "i")))
(defun romanize (arabic-numeral numerals roman-numeral)
(if (= arabic-numeral 0)
roman-numeral
(if (>= arabic-numeral (caar numerals))
(romanize (- arabic-numeral (caar numerals)) numerals (string-append roman-numeral (cadar numerals)))
(romanize arabic-numeral (cdr numerals) roman-numeral))))
(romanize n roman-numerals ""))
; test the function:
(display (mapcar roman '(10 2016 800 2769 1666 476 1453)))
```
```txt
(x mmxvi dccc mmdcclxix mdclxvi cdlxxvi mcdliii)
```
## XSLT
```xslt
13
1
1
1
1
```
## Yabasic
```Yabasic
roman$ = "M, CM, D, CD, C, XC, L, XL, X, IX, V, IV, I"
decml$ = "1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1"
sub toRoman$(value)
local res$, i, roman$(1), decml$(1), long
long = token(roman$, roman$(), ", ")
long = token(decml$, decml$(), ", ")
for i=1 to long
while(value >= val(decml$(i)))
res$ = res$ + roman$(i)
value = value - val(decml$(i))
wend
next i
return res$
end sub
print 400, " ", toRoman$(400)
print 1990, " ", toRoman$(1990)
print 2008, " ", toRoman$(2008)
print 2009, " ", toRoman$(2009)
print 1666, " ", toRoman$(1666)
print 3888, " ", toRoman$(3888)
//Output:
// 400 = CD
// 1990 = MCMXC
// 2008 = MMVIII
// 2009 = MMIX
// 1666 = MDCLXVI
// 3888 = MMMDCCCLXXXVIII
```
## VBA
```vb
Private Function roman(n As Integer) As String
roman = WorksheetFunction.roman(n)
End Function
Public Sub main()
s = [{10, 2016, 800, 2769, 1666, 476, 1453}]
For Each x In s
Debug.Print roman(CInt(x)); " ";
Next x
End Sub
```
```txt
X MMXVI DCCC MMDCCLXIX MDCLXVI CDLXXVI MCDLIII
```
## zkl
```zkl
var [const] romans = L(
L("M", 1000), L("CM", 900), L("D", 500), L("CD", 400), L("C", 100),
L("XC", 90), L("L", 50), L("XL", 40), L("X", 10), L("IX", 9),
L("V", 5), L("IV", 4), L("I", 1));
fcn toRoman(i){ // convert int to a roman number
reg text = "";
foreach R,N in (romans){ text += R*(i/N); i = i%N; }
return(text);
}
```
```txt
toRoman(1990) //-->"MCMXC"
toRoman(2008) //-->"MMVIII"
toRoman(1666) //-->"MDCLXVI"
```
## Zsh
Based on the python solution.
```zsh
function printroman () {
local -a conv
local number=$1 div rom num out
conv=(I 1 IV 4 V 5 IX 9 X 10 XL 40 L 50 XC 90 C 100 CD 400 D 500 CM 900 M 1000)
for num rom in ${(Oa)conv}; do
(( div = number / num, number = number % num ))
while (( div-- > 0 )); do
out+=$rom
done
done
echo $out
}
```