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{{task|Basic language learning}} [[Category:Functions and subroutines]] {{omit from|GUISS}}

;Task: Show how to return more than one value from a function.

ACL2

;; To return multiple values:
(defun multiple-values (a b)
   (mv a b))

;; To extract the values:
(mv-let (x y)
        (multiple-values 1 2)
   (+ x y))

Ada

Ada functions can only return one type. That type could be an array or record holding multiple values, but the usual method for returning several values is using a procedure with 'out' parameters. By default, all parameters are 'in', but can also be 'out', 'in out' and 'access'. Writing to an 'out' parameter simply changes the value of the variable passed to the procedure.


with Ada.Text_IO; use Ada.Text_IO;
procedure MultiReturn is
   procedure SumAndDiff (x, y : Integer; sum, diff : out Integer) is begin
      sum := x + y;
      diff := x - y;
   end SumAndDiff;
   inta : Integer := 5;
   intb : Integer := 3;
   thesum, thediff : Integer;
begin
   SumAndDiff (inta, intb, thesum, thediff);
   Put_Line ("Sum:" & Integer'Image (thesum));
   Put_Line ("Diff:" & Integer'Image (thediff));
end MultiReturn;

{{out}}


Sum: 8
Diff: 2

Agena

Agena allows functions to return multiple values.

Tested with Agena 2.9.5 Win32

# define a function returning three values
mv := proc() is
    return 1, 2, "three"
end ; # mv

scope # test the mv() proc
    local a, b, c := mv();
    print( c, b, a )
epocs

ALGOL 68

{{works with|ALGOL 68G|Any - tested with release 2.6.win32}} Procedures in Algol 68 can only return one value, so to return multiple values, a structure (or array if all the values have the same mode) can be used.

# example mode for returning multiple values from a procedure #
MODE PAIR = STRUCT( STRING name, INT value );

# procedure returning multiple values via a structure #
PROC get pair = ( INT a )PAIR:
    CASE a
    IN #1#    ( "H",  0 )
    ,  #2#    ( "He", 1 )
    ,  #3#    ( "Li", 3 )
    OUT       ( "?",  a )
    ESAC
;

main: (
    # use the result as a whole #
    print( ( get pair( 3 ), newline ) );
    # access the components separately #
    print( ( name OF get pair( 1 ), value OF get pair( 2 ), newline ) )
)

{{out}}


Li         +3
H         +1

ALGOL W

Algol W procedures can't return arrays but records can be used to return multiple values.

begin
    % example using a record type to return multiple values from a procedure %
    record Element ( string(2) symbol; integer atomicNumber );
    reference(Element) procedure getElement( integer value n ) ;
    begin
        Element( if      n < 1 then   "?<"
                 else if n > 3 then   "?>"
                 else case n of ( %1% "H"
                                , %2% "He"
                                , %3% "Li"
                                )
               , n
               )
    end getElement ;
    % test the procedure %
    begin
        reference(Element) elementData;
        for n := 0 until 4 do begin
            elementData := getElement(n);
            write( s_w := 0, i_w := 1
                 , atomicNumber(elementData)
                 , " "
                 , symbol(elementData)
                 );
        end
    end

end.

ANSI Standard BASIC

The most straightforward way of returning multiple values is to specify them as parameters.

100 DECLARE EXTERNAL SUB sumdiff
110 !
120 CALL sumdiff(5, 3, sum, diff)
130 PRINT "Sum is "; sum
140 PRINT "Difference is "; diff
150 END
160 !
170 EXTERNAL SUB sumdiff(a, b, c, d)
180 LET c = a + b
190 LET d = a - b
200 END SUB

ATS

Every function returns one value. The conventional way to return multiple values is to return a tuple.

//
#include
"share/atspre_staload.hats"
//
(* ****** ****** *)

fun addsub
(
  x: int, y: int
) : (int, int) = (x+y, x-y)

(* ****** ****** *)

implement
main0 () = let
  val (sum, diff) = addsub (33, 12)
in
  println! ("33 + 12 = ", sum);
  println! ("33 - 12 = ", diff);
end (* end of [main0] *)

AutoHotkey

{{works with|AutoHotkey_L}} Functions may return one value. The conventional way to return multiple values is to bundle them into an Array.

addsub(x, y) {
  return [x + y, x - y]
}

AutoIt

Return an array.


Func _AddSub($iX, $iY)
Local $aReturn[2]
$aReturn[0] = $iX + $iY
$aReturn[1] = $iX - $iY
Return $aReturn
EndFunc

BASIC

=

BaCon

= BaCon can return homogeneous dynamic arrays, or RECORD data holding heterogeneous types.

' Return multiple values
RECORD multi
    LOCAL num
    LOCAL s$[2]
END RECORD

FUNCTION f(n) TYPE multi_type
    LOCAL r = { 0 } TYPE multi_type
    r.num = n
    r.s$[0] = "Hitchhiker's Guide"
    r.s$[1] = "Douglas Adams"
    RETURN r
END FUNCTION

DECLARE rec TYPE multi_type
rec = f(42)
PRINT rec.num
PRINT rec.s$[0]
PRINT rec.s$[1]

{{out}}

prompt$ ./return-multiple
42
Hitchhiker's Guide
Douglas Adams

=

BBC BASIC

= The most straightforward way of returning multiple values is to specify them as RETURNed parameters.

      PROCsumdiff(5, 3, sum, diff)
      PRINT "Sum is " ; sum
      PRINT "Difference is " ; diff
      END

      DEF PROCsumdiff(a, b, RETURN c, RETURN d)
      c = a + b
      d = a - b
      ENDPROC

==={{header|IS-BASIC}}=== 100 NUMERIC SUM,DIFF 110 CALL SUMDIFF(5,3,SUM,DIFF) 120 PRINT "Sum is";SUM:PRINT "Difference is";DIFF 130 END 140 DEF SUMDIFF(A,B,REF C,REF D) 150 LET C=A+B:LET D=A-B 160 END DEF




## Bracmat

{{trans|Haskell}}
Every function returns one value. The conventional way to return multiple values is to return a tuple.

```bracmat
(addsub=x y.!arg:(?x.?y)&(!x+!y.!x+-1*!y));

You can use pattern matching to extract the components:

( addsub$(33.12):(?sum.?difference)
& out$("33 + 12 = " !sum)
& out$("33 - 12 = " !difference)
);

{{out}}

33 + 12 =  45
33 - 12 =  21

C

C has structures which can hold multiple data elements of varying types.

#include <stdio.h>

typedef struct{
	int integer;
	float decimal;
	char letter;
	char string[100];
	double bigDecimal;
}Composite;

Composite example()
{
	Composite C = {1, 2.3, 'a', "Hello World", 45.678};
	return C;
}


int main()
{
	Composite C = example();

	printf("Values from a function returning a structure : { %d, %f, %c, %s, %f}\n", C.integer, C.decimal, C.letter, C.string, C.bigDecimal);

	return 0;
}

{{out}}


Values from a function returning a structure : { 1, 2.300000, a, Hello World, 45.678000}

C99 and above also allow structure literals to refer to the name, rather than position, of the element to be initialized:

#include <stdio.h>

typedef struct {
    char *first, *last;
} Name;

Name whatsMyName() {
    return (Name) {
        .first = "James",
        .last = "Bond",
    };
}

int main() {
    Name me = whatsMyName();
    printf("The name's %s. %s %s.\n", me.last, me.first, me.last);
    return 0;
}

{{out}}

The name's Bond. James Bond.

C++

Since C++11, the C++-standard-library includes tuples, as well as an easy way to destructure them.

#include <algorithm>
#include <array>
#include <cstdint>
#include <iostream>
#include <tuple>

std::tuple<int, int> minmax(const int * numbers, const std::size_t num) {
   const auto maximum = std::max_element(numbers, numbers + num);
   const auto minimum = std::min_element(numbers, numbers + num);
   return std::make_tuple(*minimum, *maximum) ;
}

int main( ) {
   const auto numbers = std::array<int, 8>{{17, 88, 9, 33, 4, 987, -10, 2}};
   int min{};
   int max{};
   std::tie(min, max) = minmax(numbers.data(), numbers.size());
   std::cout << "The smallest number is " << min << ", the biggest " << max << "!\n" ;
}

{{out}}

The smallest number is -10, the biggest 987!
## C# The preferred way to return multiple values in C# is to use "out" paremeters on the method. This can be in addition to the value returned by the method. ```c sharp using System; using System.Collections.Generic; using System.Linq; class ReturnMultipleValues { static void Main() { var values = new[] { 4, 51, 1, -3, 3, 6, 8, 26, 2, 4 }; int max, min; MinMaxNum(values, out max, out min); Console.WriteLine("Min: {0}\nMax: {1}", min, max); } static void MinMaxNum(IEnumerable nums, out int max, out int min) { var sortedNums = nums.OrderBy(num => num).ToArray(); max = sortedNums.Last(); min = sortedNums.First(); } } ``` {{out}} ```txt Min: -3 Max: 51 ``` ## Clipper Every function returns one value. The conventional way to return multiple values is to bundle them into an array. ```Clipper Function Addsub( x, y ) Return { x+y, x-y } ``` ## Clojure Multiple values can be returned by packaging them in a vector. At receiving side, these arguments can be obtained individually by using [http://blog.jayfields.com/2010/07/clojure-destructuring.html destructuring]. ```clojure (defn quot-rem [m n] [(quot m n) (rem m n)]) ; The following prints 3 2. (let [[q r] (quot-rem 11 3)] (println q) (println r)) ``` In complex cases, it would make more sense to return a map, which can be destructed in a similar manner. ```clojure (defn quot-rem [m n] {:q (quot m n) :r (rem m n)}) ; The following prints 3 2. (let [{:keys [q r]} (quot-rem 11 3)] (println q) (println r)) ``` ## CMake ```cmake # Returns the first and last characters of string. function(firstlast string first last) # f = first character. string(SUBSTRING "${string}" 0 1 f) # g = last character. string(LENGTH "${string}" length) math(EXPR index "${length} - 1") string(SUBSTRING "${string}" ${index} 1 g) # Return both characters. set("${first}" "${f}" PARENT_SCOPE) set("${last}" "${g}" PARENT_SCOPE) endfunction(firstlast) firstlast("Rosetta Code" begin end) message(STATUS "begins with ${begin}, ends with ${end}") ``` ## COBOL COBOL normally passes data BY REFERENCE, which is the default mode, effectively making the arguments modifiable. User Defined Functions return a single argument, but that argument can be a group item. Most large scale COBOL programs will attempt to keep from repeating itself, in terms of data layouts, using external copy books and the COBOL COPY statement. ''This example uses in source REPLACE to avoid copy books.'' {{works with|GnuCOBOL}} ```COBOL identification division. program-id. multiple-values. environment division. configuration section. repository. function multiples function all intrinsic. REPLACE ==:linked-items:== BY == 01 a usage binary-long. 01 b pic x(10). 01 c usage float-short. == ==:record-item:== BY == 01 master. 05 ma usage binary-long. 05 mb pic x(10). 05 mc usage float-short. ==. data division. working-storage section. :linked-items: :record-item: procedure division. sample-main. move 41 to a move "aaaaabbbbb" to b move function e to c display "Original: " a ", " b ", " c call "subprogram" using a b c display "Modified: " a ", " b ", " c move multiples() to master display "Multiple: " ma ", " mb ", " mc goback. end program multiple-values. *> subprogram identification division. program-id. subprogram. data division. linkage section. :linked-items: procedure division using a b c. add 1 to a inspect b converting "a" to "b" divide 2 into c goback. end program subprogram. *> multiples function identification division. function-id. multiples. data division. linkage section. :record-item: procedure division returning master. move 84 to ma move "multiple" to mb move function pi to mc goback. end function multiples. ``` {{out}} ```txt prompt$ cobc -xj multiple-values.cob Original: +0000000041, aaaaabbbbb, 2.7182817 Modified: +0000000042, bbbbbbbbbb, 1.3591409 Multiple: +0000000084, multiple , 3.1415927 ``` ## Common Lisp Besides the obvious method of passing around a list, Common Lisp also allows a function to return multiple values. When citing the return values, if no interest is shown for multiple values, only the first (the primary return value) is used. Multiple values are not a data structure such as a tuple, list or array. They are a true mechanism for returning multiple values. Returning a single value is accomplished by evaluating an expression (which itself yields a single value) at the end of a body of forms. ```lisp (defun return-three () 3) ``` The next possibility is that of returning no values at all. For this, the values function is used, with no arguments: ```lisp (defun return-nothing () (values)) ``` To combine the values of multiple expressions into a multi-value return, values is used with arguments. The following is from an interactive [[CLISP]] session. CLISP's listener shows multiple values separated by a semicolon: ```lisp [1]> (defun add-sub (x y) (values-list (list (+ x y) (- x y)))) ADD-SUB [2]> (add-sub 4 2) ; 6 (primary) and 2 6 ; 2 [3]> (add-sub 3 1) ; 4 (primary) and 2 4 ; 2 [4]> (+ (add-sub 4 2) (add-sub 3 1)) ; 6 + 4 10 [5]> (multiple-value-call #'+ (add-sub 4 2) (add-sub 3 1)) ; 6+2+4+2 14 ``` What happens if something tries to use the value of a form which returned (values)? In this case the behavior defaults to taking the value nil: ```lisp (car (values)) ;; no error: same as (car nil) ``` What if the values function is applied to some expressions which also yield multiple values, or which do not yield any values? The answer is that only the primary value is taken from each expression, or the value nil for any expression which did not yield a value: ```lisp (values (values 1 2 3) (values) 'a) ``` yields three values: ```txt -> 1; NIL; A ``` This also means that values can be used to reduce a multiple value to a single value: ```lisp ;; return exactly one value, no matter how many expr returns, ;; nil if expr returns no values (values expr) ``` Multiple values are extracted in several ways. 1. Binding to variables: ```lisp (multiple-value-bind (dividend remainder) (truncate 16 3) ;; in this scope dividend is 5; remainder is 1 ) ``` 2. Conversion to a list: ```lisp (multiple-value-list (truncate 16 3)) ;; yields (5 1) ``` 3. Reification of multiple values as arguments to another function: ```lisp ;; pass arguments 5 1 to +, resulting in 6: (multiple-value-call #'+ (truncate 16 3)) ``` 4. Assignment to variables: ```lisp ;; assign 5 to dividend, 1 to remainder: (multiple-value-setq (dividend remainder) (truncate 16 1)) ``` (values ...) syntax is treated as a multiple value place by setf and other operators, allowing the above to be expressed this way: ```lisp (setf (values dividend remainder) (truncate 16 1)) ``` ## D ```d import std.stdio, std.typecons, std.algorithm; mixin template ret(string z) { mixin({ string res; auto r = z.split(" = "); auto m = r[0].split(", "); auto s = m.join("_"); res ~= "auto " ~ s ~ " = " ~ r[1] ~ ";"; foreach(i, n; m){ res ~= "auto " ~ n ~ " = " ~ s ~ "[" ~ i.to!string ~ "];\n"; } return res; }()); } auto addSub(T)(T x, T y) { return tuple(x + y, x - y); } void main() { mixin ret!q{ a, b = addSub(33, 12) }; writefln("33 + 12 = %d\n33 - 12 = %d", a, b); } ``` {{out}} ```txt 33 + 12 = 45 33 - 12 = 21 ``` ## Dc Define a divmod macro ~ which takes a b on the stack and returns a/b a%b. ```dc [ S1 S2 l2 l1 / L2 L1 % ] s~ 1337 42 l~ x f ``` {{out}} ```txt 35 31 ``` =={{header|Déjà Vu}}== ```dejavu function-returning-multiple-values: 10 20 !print !print function-returning-multiple-values ``` {{out}} ```txt 10 20 ``` =={{header|Delphi}}/{{header|Pascal}}== Delphi functions return a single value, but var parameters of a function or procedure can be modified and act as return values. ```Delphi program ReturnMultipleValues; {$APPTYPE CONSOLE} procedure GetTwoValues(var aParam1, aParam2: Integer); begin aParam1 := 100; aParam2 := 200; end; var x, y: Integer; begin GetTwoValues(x, y); Writeln(x); Writeln(y); end. ``` ## Dyalect A typical way to return multiple values in Dyalect is to use tuples: ```Dyalect func divRem(x, y) { (x / y, x % y) } ``` ## EchoLisp One can return the result of the '''values''' function, or a list. ```scheme (define (plus-minus x y) (values (+ x y) (- x y))) (plus-minus 3 4) → 7 -1 (define (plus-minus x y) (list (+ x y) (- x y))) (plus-minus 3 4) → (7 -1) ``` ## ECL MyFunc(INTEGER i1,INTEGER i2) := FUNCTION RetMod := MODULE EXPORT INTEGER Add := i1 + i2; EXPORT INTEGER Prod := i1 * i2; END; RETURN RetMod; END; //Reference each return value separately: MyFunc(3,4).Add; MyFunc(3,4).Prod; ``` ## Eiffel Every function returns one value. Multiple values can be returned in a tuple. ```Eiffel some_feature: TUPLE do Result := [1, 'j', "r"] end ``` Greater control over the type of return values can also be enforced by explicitly declaring the type of the generic parameters. ```Eiffel some_feature: TUPLE[INTEGER_32, CHARACTER_8, STRING_8] do --Result := [ ] -- compile error --Result := [1, "r", 'j'] -- also compile error Result := [1, 'j', "r"] -- okay Result := [1, 'j', "r", 1.23] -- also okay end ``` ## Elena ELENA 4.1 : ```elena import system'routines; import extensions; extension op { MinMax(ref int minVal, ref int maxVal) { var ordered := self.ascendant(); minVal := ordered.FirstMember; maxVal := ordered.LastMember } } public program() { var values := new int[]::(4, 51, 1, -3, 3, 6, 8, 26, 2, 4); values.MinMax(ref int min, ref int max); console.printLine("Min: ",min," Max: ",max) } ``` {{out}} ```txt Min: -3 Max: 51 ``` ## Elixir Elixir returns in the tuple form when returning more than one value. ```elixir defmodule RC do def addsub(a, b) do {a+b, a-b} end end {add, sub} = RC.addsub(7, 4) IO.puts "Add: #{add},\tSub: #{sub}" ``` {{out}} ```txt Add: 11, Sub: 3 ``` ## Erlang ```erlang % Put this code in return_multi.erl and run it as "escript return_multi.erl" -module(return_multi). main(_) -> {C, D, E} = multiply(3, 4), io:format("~p ~p ~p~n", [C, D, E]). multiply(A, B) -> {A * B, A + B, A - B}. ``` {{out}} ```txt 12 7 -1 ``` ## ERRE FUNCTIONs in ERRE language return always a single value, but PROCEDUREs can return multiple values defining a parameter output list in procedure declaration using '->' separator. ```ERRE PROGRAM RETURN_VALUES PROCEDURE SUM_DIFF(A,B->C,D) C=A+B D=A-B END PROCEDURE BEGIN SUM_DIFF(5,3->SUM,DIFF) PRINT("Sum is";SUM) PRINT("Difference is";DIFF) END PROGRAM ``` ## Euphoria Any Euphoria object can be returned. A sequence of objects can be returned, made from multiple data types as in this example. ```euphoria include std\console.e --only for any_key, to help make running this program easy on windows GUI integer aWholeNumber = 1 atom aFloat = 1.999999 sequence aSequence = {3, 4} sequence result = {} --empty initialized sequence function addmultret(integer first, atom second, sequence third)--takes three kinds of input, adds them all into one element of the.. return (first + second + third[1]) + third[2] & (first * second * third[1]) * third[2] --..output sequence and multiplies them into.. end function --..the second element result = addmultret(aWholeNumber, aFloat, aSequence) --call function, assign what it gets into result - {9.999999, 23.999988} ? result any_key() ``` {{out}} ```txt {9.999999,23.999988} Press Any Key to continue... ``` =={{header|F_Sharp|F#}}== A function always returns exactly one value. To return multiple results, they are typically packed into a tuple: ```fsharp let addSub x y = x + y, x - y let sum, diff = addSub 33 12 printfn "33 + 12 = %d" sum printfn "33 - 12 = %d" diff ``` Output parameters from .NET APIs are automatically converted to tuples by the compiler. It is also possible to use output parameters explicitly with the byref keyword, but this is rarely necessary. ## Factor With stack-oriented languages like Factor, a function returns multiple values by pushing them on the data stack. For example, this word ''*/'' pushes both x*y and x/y. ```factor USING: io kernel math prettyprint ; IN: script : */ ( x y -- x*y x/y ) [ * ] [ / ] 2bi ; 15 3 */ [ "15 * 3 = " write . ] [ "15 / 3 = " write . ] bi* ``` Its stack effect declares that ''*/'' always returns 2 values. To return a variable number of values, a word must bundle those values into a [[sequence]] (perhaps an array or vector). For example, ''factors'' (defined in ''math.primes.factors'' and demonstrated at [[Prime decomposition#Factor]]) returns a sequence of prime factors. ## FALSE ```false [\$@$@*@@/]f: { in: a b, out: a*b a/b } 6 2f;! .` ,. { 3 12 } ``` =={{header|Fōrmulæ}}== In [http://wiki.formulae.org/Return_multiple_values this] page you can see the solution of this task. Fōrmulæ programs are not textual, visualization/edition of programs is done showing/manipulating structures but not text ([http://wiki.formulae.org/Editing_F%C5%8Drmul%C3%A6_expressions more info]). Moreover, there can be multiple visual representations of the same program. Even though it is possible to have textual representation —i.e. XML, JSON— they are intended for transportation effects more than visualization and edition. The option to show Fōrmulæ programs and their results is showing images. Unfortunately images cannot be uploaded in Rosetta Code. ## Forth It is natural to return multiple values on the parameter stack. Many built-in operators and functions do so as well ('''/mod''', '''open-file''', etc.). ```forth : muldiv ( a b -- a*b a/b ) 2dup / >r * r> ; ``` ## Fortran {{trans|Haskell}} ```Fortran module multiple_values implicit none type res integer :: p, m end type contains function addsub(x,y) result(r) integer :: x, y type(res) :: r r%p = x+y r%m = x-y end function end module program main use multiple_values print *, addsub(33, 22) end program ``` ## FreeBASIC ```freebasic ' FB 1.05.0 Win64 ' One way to return multiple values is to use ByRef parameters for the additional one(s) Function tryOpenFile (fileName As String, ByRef fileNumber As Integer) As Boolean Dim result As Integer fileNumber = FreeFile result = Open(fileName For Input As # fileNumber) If result <> 0 Then fileNumber = 0 Return False Else Return True End If End Function Dim fn As Integer Var b = tryOpenFile("xxx.zyz", fn) '' this file doesn't exist Print b, fn b = tryOpenFile("input.txt", fn) '' this file does exist Print b, fn Close # fn ' Another way is to use a user defined type Type FileOpenInfo opened As Boolean fn As Integer End Type Function tryOpenFile2(fileName As String) As FileOpenInfo Dim foi As FileOpenInfo foi.fn = FreeFile Dim result As Integer result = Open(fileName For Input As # foi.fn) If result <> 0 Then foi.fn = 0 foi.opened = False Else foi.Opened = True End If Return foi End Function Print Var foi = tryOpenFile2("xxx.zyz") Print foi.opened, foi.fn foi = tryOpenFile2("input.txt") Print foi.opened, foi.fn Close # foi.fn Print Print "Press any key to quit" Sleep ``` {{out}} ```txt false 0 true 1 false 0 true 1 ``` ## Frink The most common way of returning multiple values from a function is to return them as an array, which can be disassembled and set into individual variables on return. ```frink divMod[a, b] := [a div b, a mod b] [num, remainder] = divMod[10, 3] ``` ## FunL {{trans|Scala}} ```funl def addsub( x, y ) = (x + y, x - y) val (sum, difference) = addsub( 33, 12 ) println( sum, difference, addsub(33, 12) ) ``` {{out}} ```txt 45, 21, (45, 21) ``` ## FutureBasic FutureBasic offers several ways to return multiple values from a function: by passing pointers to multiple values in and out of functions; global records (structures); global containers (imagine a global bit bucket that can hold up to 2GBs of data); and global arrays of either the standard kind, or of FB's dynamic arrays. Here is an example of returning multiple values using pointers: ```futurebasic include "ConsoleWindow" local fn ReturnMultipleValues( strIn as Str255, strOut as ^Str255, letterCount as ^long ) dim as Str255 s // Test if incoming string is empty, and exit function if it is if strIn[0] == 0 then exit fn // Prepend this string to incoming string and return it s = "Here is your original string: " strOut.nil$ = s + strIn // Get length of combined string and return it // Note: In FutureBasic string[0] is interchangeable with Len(string) letterCount.nil& = strIn[0] + s[0] end fn dim as Str255 outStr dim as long outCount fn ReturnMultipleValues( "Hello, World!", @outStr, @outCount ) print outStr; ". The combined strings have"; outCount; " letters in them." ``` Output: ```txt Here is your original string: Hello, World!. The combined strings have 43 letters in them. ``` Another way to pass multiple values from a function is with records (AKA structures): include "ConsoleWindow" // Elements in global array _maxDim = 3 begin record Addresses dim as Str63 name dim as Str15 phone dim as long zip end record begin globals dim as Addresses gAddressData(_maxDim) end globals local fn FillRecord( array(_maxDim) as Addresses ) array.name(0) = "John Doe" array.name(1) = "Mary Jones" array.name(2) = "Bill Smith array.phone(0) = "555-359-4411" array.phone(1) = "555-111-2211" array.phone(2) = "555-769-8071" array.zip(0) = 12543 array.zip(1) = 67891 array.zip(2) = 54321 end fn // Pass address of global array to fill it fn FillRecord( gAddressData(0) ) dim as short i for i = 0 to 2 print gAddressData.name(i); ", "; print gAddressData.phone(i); ", Zip:"; print gAddressData.zip(i) next ``` Output: ```txt John Doe, 555-359-4411, Zip: 12543 Mary Jones, 555-111-2211, Zip: 67891 Bill Smith, 555-769-8071, Zip: 54321 ``` You can also use global arrays to return multiple values from a function as in this example: include "ConsoleWindow" // Elements in global array _maxDim = 3 begin globals dim as Str31 gAddressArray(_maxDim, _maxDim) end globals local fn FillRecord( array(_maxDim, _maxDim) as Str31 ) array( 0, 0 ) = "John Doe" array( 1, 0 ) = "Mary Jones" array( 2, 0 ) = "Bill Smith array( 0, 1 ) = "555-359-4411" array( 1, 1 ) = "555-111-2211" array( 2, 1 ) = "555-769-8071" array( 0, 2 ) = "12543" array( 1, 2 ) = "67891" array( 2, 2 ) = "54321" end fn // Pass address of global array to fill it fn FillRecord( gAddressArray( 0, 0 ) ) dim as short i, j for i = 0 to 2 j = 0 print gAddressArray(i, j ); ", "; print gAddressArray(i, j + 1); ", Zip: "; print gAddressArray(i, j + 1) next ``` Output: ```txt John Doe, 555-359-4411, Zip: 555-359-4411 Mary Jones, 555-111-2211, Zip: 555-111-2211 Bill Smith, 555-769-8071, Zip: 555-769-8071 ``` Here is another example using FB's containers -- bit buckets that can hold up to 2GB of data contingent on system memory. include "ConsoleWindow" begin globals // An FB container can hold up to 2GB of data, contingent on system memory dim as container gC1, gC2 end globals local fn ReturnMultipleValuesInContainers // Fill container with strings from inside function gC1 = "Twas brillig, and the slithy toves" + chr$(13) gC1 += "Did gyre and gimble in the wabe;" + chr$(13) gC1 += "All mimsy were the borogoves," + chr$(13) gC1 += "And the mome raths outgrabe." + chr$(13) gC1 += "'Beware the Jabberwock, my son!" + chr$(13) gC1 += "The jaws that bite, the claws that catch!" + chr$(13) gC1 += "Beware the Jubjub bird, and shun" + chr$(13) gC1 += "The frumious Bandersnatch!'" + chr$(13) // Fill another container with numbers gC2 = "10254"+ chr$(13) gC2 += "37" + chr$(13) gC2 += "64" + chr$(13) end fn local fn ReturnNewMultipleValuesInContainers gC1 = "Jabberwocky is gone, but here is some new text." + chr$(13) gC2 = "1000000" end fn // Test to see containers are empty: print gC1 : print gC2 // Fill the containers using a function fn ReturnMultipleValuesInContainers // Check results print gC1 : print : print gC2 // Empty the containers gC1 = "" : gC2 = "" // Fill with another function fn ReturnNewMultipleValuesInContainers // Check the new results print gC1 : print gC2 ``` Output: ```txt Twas brillig, and the slithy toves Did gyre and gimble in the wabe; All mimsy were the borogoves, And the mome raths outgrabe. 'Beware the Jabberwock, my son! The jaws that bite, the claws that catch! Beware the Jubjub bird, and shun The frumious Bandersnatch!' 10254 37 64 Jabberwocky is gone, but here is some new text. 1000000 ``` ## Go Functions can return multiple values in Go: ```go func addsub(x, y int) (int, int) { return x + y, x - y } ``` Or equivalently using named return style: ```go func addsub(x, y int) (sum, difference int) { sum = x + y difference = x - y return } ``` When a function returns multiple values, you must assign to a comma-separated list of targets: ```go sum, difference := addsub(33, 12) fmt.Printf("33 + 12 = %d\n", sum) fmt.Printf("33 - 12 = %d\n", difference) ``` ## Groovy In Groovy functions return one value. One way to return multiple ones is to use anonymous maps as a sort of tuple. ```groovy def addSub(x,y) { [ sum: x+y, difference: x-y ] } ``` Result: ```groovy addSub(10,12) ["sum":22, "difference":-2] ``` And although Groovy functions only return one value, Groovy ''assignments'' of Iterable objects (lists, arrays, sets, etc.) can be distributed across multiple ''variables'', like this: ```groovy def addSub2(x,y) { [ x+y , x-y ] } def (sum, diff) = addSub2(50, 5) assert sum == 55 assert diff == 45 ``` If there are fewer elements than variables, the leftover variables are assigned null. If there are more elements than variables, the last variable is assigned the collected remainder of the elements. ## Harbour Every function returns one value. The conventional way to return multiple values is to bundle them into an array. ```visualfoxpro FUNCTION Addsub( x, y ) RETURN { x + y, x - y } ``` ## Haskell Every function returns one value. The conventional way to return multiple values is to return a tuple. ```haskell addsub x y = (x + y, x - y) ``` You can use pattern matching to extract the components: ```haskell main = do let (sum, difference) = addsub 33 12 putStrLn ("33 + 12 = " ++ show sum) putStrLn ("33 - 12 = " ++ show difference) ``` =={{header|Icon}} and {{header|Unicon}}== Icon and Unicon values range from simple atomic values like integers and strings to structures like lists, tables, sets, records. The contents of structures are heterogeneous and any of them could be used to return multiple values all at once. Additionally, generators are supported that return multiple results one at a time as needed. The following examples return 1, 2, 3 in different ways: ```Icon procedure retList() # returns as ordered list return [1,2,3] end procedure retSet() # returns as un-ordered list insert(S := set(),3,1,2) return S end procedure retLazy() # return as a generator suspend 1|2|3 end procedure retTable() # return as a table T := table() T["A"] := 1 T["B"] := 2 T["C"] := 3 return T end record retdata(a,b,c) procedure retRecord() # return as a record, least general method return retdata(1,2,3) end ``` ## J To return multiple values in J, you return an array which contains multiple values. Since the only data type in J is array (this is an oversimplification, from some perspectives - but those issues are out of scope for this task), this is sort of like asking how to return only one value in another language. ```j 1 2+3 4 4 6 ``` ## Java {{trans|NetRexx}} ```Java import java.util.List; import java.util.ArrayList; import java.util.Map; import java.util.HashMap; // ### ======================================================================= public class RReturnMultipleVals { public static final String K_lipsum = "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua."; public static final Long K_1024 = 1024L; public static final String L = "L"; public static final String R = "R"; // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ public static void main(String[] args) throws NumberFormatException{ Long nv_; String sv_; switch (args.length) { case 0: nv_ = K_1024; sv_ = K_lipsum; break; case 1: nv_ = Long.parseLong(args[0]); sv_ = K_lipsum; break; case 2: nv_ = Long.parseLong(args[0]); sv_ = args[1]; break; default: nv_ = Long.parseLong(args[0]); sv_ = args[1]; for (int ix = 2; ix < args.length; ++ix) { sv_ = sv_ + " " + args[ix]; } break; } RReturnMultipleVals lcl = new RReturnMultipleVals(); Pair rvp = lcl.getPairFromPair(nv_, sv_); // values returned in a bespoke object System.out.println("Results extracted from a composite object:"); System.out.printf("%s, %s%n%n", rvp.getLeftVal(), rvp.getRightVal()); List rvl = lcl.getPairFromList(nv_, sv_); // values returned in a Java Collection object System.out.println("Results extracted from a Java Colections \"List\" object:"); System.out.printf("%s, %s%n%n", rvl.get(0), rvl.get(1)); Map rvm = lcl.getPairFromMap(nv_, sv_); // values returned in a Java Collection object System.out.println("Results extracted from a Java Colections \"Map\" object:"); System.out.printf("%s, %s%n%n", rvm.get(L), rvm.get(R)); } // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ // Return a bespoke object. // Permits any number and type of value to be returned public Pair getPairFromPair(T vl_, U vr_) { return new Pair(vl_, vr_); } // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ // Exploit Java Collections classes to assemble a collection of results. // This example uses java.util.List public List getPairFromList(Object nv_, Object sv_) { List rset = new ArrayList(); rset.add(nv_); rset.add(sv_); return rset; } // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ // Exploit Java Collections classes to assemble a collection of results. // This example uses java.util.Map public Map getPairFromMap(Object nv_, Object sv_) { Map rset = new HashMap(); rset.put(L, nv_); rset.put(R, sv_); return rset; } // ### ===================================================================== private static class Pair { private L leftVal; private R rightVal; public Pair(L nv_, R sv_) { setLeftVal(nv_); setRightVal(sv_); } public void setLeftVal(L nv_) { leftVal = nv_; } public L getLeftVal() { return leftVal; } public void setRightVal(R sv_) { rightVal = sv_; } public R getRightVal() { return rightVal; } } } ``` '''Otherwise''' ```Java public class Values { private final Object[] objects; public Values(Object ... objects) { this.objects = objects; } public T get(int i) { return (T) objects[i]; } public Object[] get() { return objects; } // to test public static void main(String[] args) { Values v = getValues(); int i = v.get(0); System.out.println(i); printValues(i, v.get(1)); printValues(v.get()); } private static Values getValues() { return new Values(1, 3.8, "text"); } private static void printValues(int i, double d) { System.out.println(i + ", " + d); } private static void printValues(Object ... objects) { for (int i=0; i 1, b => 2, c => 3 //skip a value var [a, , c] = arrBind();//assigns a => 1, c => 3 //keep final values together as array var [a, ...rest] = arrBind();//assigns a => 1, rest => [2, 3] //same return name var {foo, bar, baz} = objBind();//assigns foo => "abc", bar => "123", baz => "zzz" //different return name (ignoring baz) var {baz: foo, buz: bar} = objBind();//assigns baz => "abc", buz => "123" //keep rest of values together as object var {foo, ...rest} = objBind();//assigns foo => "abc, rest => {bar: "123", baz: "zzz"} ``` ## jq jq supports streams of JSON values, so there are two main ways in which a function can return multiple values: as a stream, or as an array. Using the same example given for the Julia entry: ```jq # To produce a stream: def addsub(x; y): (x + y), (x - y); # To produce an array: def add_subtract(x; y): [ x+y, x-y ]; ``` The builtin filter .[] streams its input if the input is an array, e.g. the expression [1,2] | .[] produces the stream: ```jq 1 2 ``` ## Julia ```julia function addsub(x, y) return x + y, x - y end ``` ```txt julia> addsub(10,4) (14,6) ``` ## Kotlin Although Kotlin doesn't support tuples as such, it does have generic Pair and Triple types which can be used to return 2 or 3 values from a function. To return more values, a data class can be used. All of these types can be automatically destructured to separate named variables. ```scala // version 1.0.6 /* implicitly returns a Pair*/ fun minmax(ia: IntArray) = ia.min() to ia.max() fun main(args: Array) { val ia = intArrayOf(17, 88, 9, 33, 4, 987, -10, 2) val(min, max) = minmax(ia) // destructuring declaration println("The smallest number is $min") println("The largest number is $max") } ``` {{out}} ```txt The smallest number is -10 The largest number is 987 ``` ## Lasso ```Lasso define multi_value() => { return (:'hello word',date) } // shows that single method call will return multiple values // the two values returned are assigned in order to the vars x and y local(x,y) = multi_value 'x: '+#x '\ry: '+#y ``` {{out}} ```txt x: hello word y: 2013-11-06 01:03:47 ``` ## Liberty BASIC Using a space-delimited string to hold the array. LB functions return only one numeric or string value, so the function returns a string from which can be separated the two desired values. ```lb data$ ="5 6 7 22 9 3 4 8 7 6 3 -5 2 1 8 9" a$ =minMax$( data$) print " Minimum was "; word$( a$, 1, " "); " & maximum was "; word$( a$, 2, " ") end function minMax$( i$) min = 1E6 max =-1E6 i =1 do t$ =word$( i$, i, " ") if t$ ="" then exit do v =val( t$) min =min( min, v) max =max( max, v) i =i +1 loop until 0 minMax$ =str$( min) +" " +str$( max) end function ``` ```txt Minimum was -5 & maximum was 22 ``` ## Lily No support for returning multiple values, but (similar to Scala), a Tuple can be returned. ```Lily define combine(a: Integer, b: String): Tuple[Integer, String] { return <[a, b]> } ``` The current version (0.17) has no support for destructuring Tuple assigns. ## Lua ```lua function addsub( a, b ) return a+b, a-b end s, d = addsub( 7, 5 ) print( s, d ) ``` ## Maple ```Maple> sumprod := ( a, b ) -> (a + b, a * b): > sumprod( x, y ); x + y, x y > sumprod( 2, 3 ); 5, 6 ``` The parentheses are needed here only because of the use of arrow ("->") notation to define the procedure. One could do, instead: ```Maple sumprod := proc( a, b ) a + b, a * b end: ``` ## Mathematica ```Mathematica addsub [x_,y_]:= List [x+y,x-y] addsub[4,2] ``` {{out}} ```txt {6,2} ``` =={{header|MATLAB}} / {{header|Octave}}== ```Matlab function [a,b,c]=foo(d) a = 1-d; b = 2+d; c = a+b; end; [x,y,z] = foo(5) ``` {{out}} ```Matlab> [x,y,z] = foo(5) x = -4 y = 7 z = 3 ``` ## Maxima ```maxima f(a, b) := [a * b, a + b]$ [u, v]: f(5, 6); [30, 11] ``` ## Mercury Mercury is a logic language. Its unification semantics permit any number of output parameters (the closest equivalent to return values). The sample code provided here centres on the addsub/4 predicate. The mode statement identifies the first two parameters as input parameters and the last two as output parameters, thus, in effect, returning two results. In this case the first output parameter returns the sum of the two inputs and the second output returns the difference of the two inputs. ### addsub.m ```mercury :- module addsub. :- interface. :- import_module io. :- pred main(io::di, io::uo) is det. :- implementation. :- import_module int, list, string. main(!IO) :- command_line_arguments(Args, !IO), filter_map(to_int, Args, CleanArgs), (length(CleanArgs, 2) -> X = det_index1(CleanArgs,1), Y = det_index1(CleanArgs,2), addsub(X, Y, S, D), format("%d + %d = %d\n%d - %d = %d\n", [i(X), i(Y), i(S), i(X), i(Y), i(D)], !IO) ; write_string("Please pass two integers on the command line.\n", !IO) ). :- pred addsub(int::in, int::in, int::out, int::out) is det. addsub(X, Y, S, D) :- S = X + Y, D = X - Y. :- end_module addsub. ``` ### Use and output ```txt $ mmc addsub.m -E && ./addsub 100 999 100 + 999 = 1099 100 - 999 = -899 ``` ### Functions and tuples Mercury is also a functional language, thus a function-based implementation is also possible. Functions in Mercury can only return a single value, but Mercury allows the use of arbitrary tuples containing multiple heterogeneous ad-hoc values which is, for all practical purposes, the same thing. The above code can be modified so that the definition of addsub/4 is now instead this function addsub/2: ```Mercury :- func addsub(int, int) = {int, int}. addsub(X, Y) = { X + Y, X - Y }. ``` Instead, now, of a predicate with two input and two output parameters of type int, addsub is a function that takes two int parameters and returns a tuple containing two int values. The call to addsub/4 in the above code is now replaced by this: ```Mercury {S, D} = addsub(X, Y), ``` All other code remains exactly the same as does the use and output of it. ### Functions and type constructors It should be noted that tuples as a construct are generally frowned upon in Mercury, relying as they do on structural type equivalence instead of nominative. The preferred approach is either to have multiple explicit output parameters on predicates or to have an explicit named type that covers the multi-return needs. An example of this follows: ```Mercury :- module addsub. :- interface. :- import_module io. :- pred main(io::di, io::uo) is det. :- implementation. :- import_module int, list, string. :- type my_result ---> twin(int, int). main(!IO) :- command_line_arguments(Args, !IO), filter_map(to_int, Args, CleanArgs), (length(CleanArgs, 2) -> X = det_index1(CleanArgs,1), Y = det_index1(CleanArgs,2), twin(S, D) = addsub(X, Y), format("%d + %d = %d\n%d - %d = %d\n", [i(X), i(Y), i(S), i(X), i(Y), i(D)], !IO) ; write_string("Please pass two integers on the command line.\n", !IO) ). :- func addsub(int, int) = my_result. addsub(X, Y) = twin(X + Y, X - Y). :- end_module addsub. ``` Here the type my_result has been provided with a twin/2 constructor that accepts two int values. Use and output of the code is, again, exactly the same. addsub/2 explicitly constructs a my_result value with the paired calculations and this is deconstructed in the call in the main predicate through unification. While the resulting code is slightly more verbose than the tuple-based version it is more strongly protected against type errors and is more explicit in its intent at the same time. ## Nemerle To return multiple values in Nemerle, package them into a tuple. ```Nemerle using System; using System.Console; using Nemerle.Assertions; module MultReturn { MinMax[T] (ls : list[T]) : T * T where T : IComparable requires ls.Length > 0 otherwise throw ArgumentException("An empty list has no extreme values.") { def greaterOf(a, b) { if (a.CompareTo(b) > 0) a else b } def lesserOf(a, b) { if (a.CompareTo(b) < 0) a else b } (ls.FoldLeft(ls.Head, lesserOf), ls.FoldLeft(ls.Head, greaterOf)) // packing tuple } Main() : void { def nums = [1, 34, 12, -5, 4, 0]; def (min, max) = MinMax(nums); // unpacking tuple WriteLine($"Min of nums = $min; max of nums = $max"); } } ``` ## NetRexx While a NetRexx method can only return a single "thing" to it's caller that "thing" can be an object which may contain a great deal of information. Typical return objects can be composite objects, Java Collection Class objects, NetRexx ''indexed strings'' etc. Another common idiom inherited from [[REXX]] is the ability to collect the return data into a simple NetRexx string. Caller can then use the PARSE instruction to deconstruct the return value and assign the parts to separate variables. ```NetRexx /* NetRexx */ options replace format comments java crossref symbols nobinary -- ### ======================================================================= class RReturnMultipleVals public properties constant L = 'L' R = 'R' K_lipsum = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.' K_1024 = 1024 -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method RReturnMultipleVals() public return -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method main(args = String[]) public static arg = Rexx(args) parse arg nv_ sv_ . if \nv_.datatype('n') then nv_ = K_1024 if sv_ = '' then sv_ = K_lipsum lcl = RReturnMultipleVals() rvr = lcl.getPair(nv_, sv_) -- multiple values returned as a string. Use PARSE to extract values parse rvr val1 val2 say 'Results extracted from a NetRexx string:' say val1',' val2 say rvr = lcl.getPairFromRexx(nv_, sv_) -- values returned in a NetRexx indexed string say 'Results extracted from a NetRexx "indexed string":' say rvr[L]',' rvr[R] say rvp = lcl.getPairFromPair(nv_, sv_) -- values returned in a bespoke object say 'Results extracted from a composite object:' say rvp.getLeftVal',' rvp.getRightVal say rvl = lcl.getPairFromList(nv_, sv_) -- values returned in a Java Collection "List" object say 'Results extracted from a Java Colections "List" object:' say rvl.get(0)',' rvl.get(1) say rvm = lcl.getPairFromMap(nv_, sv_) -- values returned in a Java Collection "Map" object say 'Results extracted from a Java Colections "Map" object:' say rvm.get(L)',' rvm.get(R) say return -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- returns the values in a NetRexx string. -- Caller can the power of PARSE to extract the results method getPair(nv_, sv_) public returns Rexx return nv_ sv_ -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- Return the values as members of a NetRexx indexed string method getPairFromRexx(nv_, sv_) public returns Rexx rval = '' rval[L] = nv_ rval[R] = sv_ return rval -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- Return a bespoke object. -- Permits any number and type of value to be returned method getPairFromPair(nv_, sv_) public returns RReturnMultipleVals.Pair rset = RReturnMultipleVals.Pair(nv_, sv_) return rset -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- Exploit Java Collections classes to assemble a collection of results. -- This example uses java.util.List method getPairFromList(nv_, sv_) public returns java.util.List rset = ArrayList() rset.add(nv_) rset.add(sv_) return rset -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- This example uses java.util.Map method getPairFromMap(nv_, sv_) public returns java.util.Map rset = HashMap() rset.put(L, nv_) rset.put(R, sv_) return rset -- ### ======================================================================= class RReturnMultipleVals.Pair dependent properties indirect leftVal rightVal -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method Pair(nv_ = parent.K_1024, sv_ = parent.K_lipsum) public setLeftVal(nv_) setRightVal(sv_) return ``` ## Nim Every function returns one value. We can return a tuple instead: ```nim proc addsub(x, y): auto = (x + y, x - y) var (a,b) = addsub(12, 15) ``` Or manipulate the parameters directly: ```nim proc addsub(x, y: int, a, b: var int) = a = x + y b = x - y var a, b: int addsub(12, 15, a, b) ``` ## Objeck Easiest way to return multiple values is to use in/out objects. The language also supports returning collections. ```objeck class Program { function : Main(args : String[]) ~ Nil { a := IntHolder->New(3); b := IntHolder->New(7); Addon(a,b); a->Get()->PrintLine(); b->Get()->PrintLine(); } function : Addon(a : IntHolder, b : IntHolder) ~ Nil { a->Set(a->Get() + 2); b->Set(b->Get() + 13); } } ``` ## OCaml Every function returns one value. The conventional way to return multiple values is to return a tuple. ```ocaml let addsub x y = x + y, x - y ``` (Note that parentheses are not necessary for a tuple literal in OCaml.) You can use pattern matching to extract the components: ```ocaml let sum, difference = addsub 33 12 in Printf.printf "33 + 12 = %d\n" sum; Printf.printf "33 - 12 = %d\n" difference ``` ## Oforth Oforth uses a data stack. A function return is everything left on the stack when the function ends, so a function can return as many objects as needed : ```Oforth import: date : returnFourValues 12 13 14 15 ; : returnOneObject [ 12, 13, 14, 15, [16, 17 ], Date now, 1.2, "abcd" ] ; "Showing four values returned on the parameter stack:" println returnFourValues .s clr "\nShowing one object containing four values returned on the parameter stack:" println returnOneObject .s clr ``` Output: ```txt Showing four values returned on the parameter stack: [1] (Integer) 15 [2] (Integer) 14 [3] (Integer) 13 [4] (Integer) 12 Showing one object containing four values returned on the parameter stack: [1] (List) [12, 13, 14, 15, [16, 17], 2016-02-05 20:55:15,778, 1.2, abcd] ``` ## ooRexx Functions and methods in ooRexx can only have a single return value, but that return value can be some sort of collection or other object that contains multiple values. For example, an array: ```ooRexx r = addsub(3, 4) say r[1] r[2] ::routine addsub use arg x, y return .array~of(x + y, x - y) ``` Output: ```txt 7 -1 ``` ## OxygenBasic Demonstrated with vectors, using OOP and a pseudo-assign trick: ```oxygenbasic ' ### ====== class vector4 ' ### ====== float w,x,y,z method values(float fw,fx,fy,fz) this <= fw, fx, fy, fz end method method values(vector4 *v) this <= v.w, v.x, v.y, v.z end method method values() as vector4 return this end method method ScaledValues(float fw,fx,fy,fz) as vector4 static vector4 v v <= w*fw, x*fx, y*fy, z*fz return v end method method ShowValues() as string string cm="," return w cm x cm y cm z end method end class vector4 aa,bb bb.values = 1,2,3,4 aa.values = bb.Values() print aa.ShowValues() 'result 1,2,3,4 aa.values = bb.ScaledValues(100,100,-100,100) print aa.ShowValues() 'result 100,200,-300,400 ``` ## PARI/GP The usual way to return multiple values is to put them in a vector: ```parigp foo(x)={ [x^2, x^3] }; ``` ## Perl Functions may return lists of values: ```perl sub foo { my ($a, $b) = @_; return $a + $b, $a * $b; } ``` ## Perl 6 Each function officially returns one value, but by returning a List or Seq you can transparently return a list of arbitrary (even infinite) size. The calling scope can destructure the list using assignment, if it so chooses: ```perl6 sub addmul($a, $b) { $a + $b, $a * $b } my ($add, $mul) = addmul 3, 7; ``` In this example, the variable $add now holds the number 10, and $mul the number 21. ## Phix Every function returns one value. You can return any number of items as elements of a sequence, and unpack them on receipt or not. ```Phix function stuff() return {"PI",'=',3.1415926535} end function string what integer op object val {what,op,val} = stuff() ``` ## PHP Every function returns one value. The conventional way to return multiple values is to bundle them into an array. ```php function addsub($x, $y) { return array($x + $y, $x - $y); } ``` You can use the list() construct to assign to multiple variables: ```php list($sum, $difference) = addsub(33, 12); echo "33 + 12 = $sum\n"; echo "33 - 12 = $difference\n"; ``` Additionally, if you specify a parameter as being a pointer, you do have the capacity to change that value. A built-in PHP example of this is preg_match() which returns a boolean value (to determine if a match was found or not), but which modifies the $matches parameter supplied to hold all the capture groups. You can achieve this simply by adding the & before the desired parameter: ```php function multiples($param1, &$param2) { if ($param1 == 'bob') { $param2 = 'is your grandmother'; return true; } return false; } echo 'First run: ' . multiples('joe', $y) . "\r\n"; echo "Param 2 from first run: '${y}'\r\n"; echo 'Second run: ' . multiples('bob', $y) . "\r\n"; echo "Param 2 from second run: '${y}'\r\n"; ``` The above will yield the following output: ```txt First run: Param 2 from first run: '' Second run: 1 Param 2 from second run: 'is your grandmother' ``` ## PicoLisp A PicoLisp function returns a single value. For multiple return values, a cons pair or a list may be used. ```PicoLisp (de addsub (X Y) (list (+ X Y) (- X Y)) ) ``` Test: ```PicoLisp : (addsub 4 2) -> (6 2) : (addsub 3 1) -> (4 2) : (+ (car (addsub 4 2)) (car (addsub 3 1))) -> 10 : (sum + (addsub 4 2) (addsub 3 1)) -> 14 ``` ## Pike Multiple values are returned through an array. An array can be assigned to separate variables. ```Pike array(int) addsub(int x, int y) { return ({ x+y, x-y }); } [int z, int w] = addsub(5,4); ``` ## PL/I Example 1 illustrates a function that returns an array: ```PL/I define structure 1 h, 2 a (10) float; declare i fixed binary; sub: procedure (a, b) returns (type(h)); declare (a, b) float; declare p type (h); do i = 1 to 10; p.a(i) = i; end; return (p); end sub; ``` Example 2 illustrates a function that returns a general data structure: ```PL/I define structure 1 customer, 2 name, 3 surname character (20), 3 given_name character (10), 2 address, 3 street character (20), 3 suburb character (20), 3 zip fixed decimal (7); sub2: procedure() returns (type(customer)); declare c type (customer); get edit (c.surname, c.given_name) (L); get edit (c.street, c.suburb, c.zip) (L); return (c); end sub2; ``` Example 3 illustrates the return of two values as a complex value: ```PL/I comp: procedure(a, b) returns (complex); declare (a, b) float; return (complex(a, b) ); end comp; ``` ## PowerShell ```PowerShell function multiple-value ($a, $b) { [pscustomobject]@{ a = $a b = $b } } $m = multiple-value "value" 1 $m.a $m.b ``` Output: ```txt value 1 ``` ## PureBasic PureBasic's procedures return only a single value. The value needs to be a standard numeric type or string. An array, map, or list can be used as a parameter to a procedure and in the process contain values to be returned as well. A pointer to memory or a structured variable may also be returned to reference multiple return values (requiring the memory to be manually freed afterwards). ```purebasic ;An array, map, or list can be used as a parameter to a procedure and in the ;process contain values to be returned as well. Procedure example_1(x, y, Array r(1)) ;array r() will contain the return values Dim r(2) ;clear and resize the array r(0) = x + y ;return these values in the array r(1) = x - y r(2) = x * y EndProcedure ;A pointer to memory or a structured variable may also be returned to reference ;multiple return values (requiring the memory to be manually freed afterwards). Procedure example_2(x, y) Protected *result.POINT = AllocateMemory(SizeOf(POINT)) *result\x = x *result\y = y ProcedureReturn *result ;*result points to a 'POINT' structure containing x and y EndProcedure If OpenConsole() Dim a(5) example_1(6, 5, a()) ;a() now contains {11, 1, 30} PrintN("Array returned with {" + Str(a(0)) + ", " + Str(a(1)) + ", " + Str(a(2)) + "}") Define *aPoint.POINT *aPoint = example_2(6, 5) ;*aPoint references structured memory containing {6, 5} PrintN("structured memory holds: (" + Str(*aPoint\x) + ", " + Str(*aPoint\y) + ")") FreeMemory(*aPoint) ;freememory Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input() CloseConsole() EndIf ``` ## Python Every function returns one value. The conventional way to return multiple values is to bundle them into a tuple. ```python def addsub(x, y): return x + y, x - y ``` (Note that parentheses are not necessary for a tuple literal in Python.) You can assign to a comma-separated list of targets: ```python sum, difference = addsub(33, 12) print "33 + 12 = %s" % sum print "33 - 12 = %s" % difference ``` There is no discernible difference between "returning multiple values" and returning a single tuple of multiple values. It is just a more pedantic/accurate statement of the mechanism employed. ## R The conventional way to return multiple values is to bundle them into a list. ```R addsub <- function(x, y) list(add=(x + y), sub=(x - y)) ``` ## Racket Racket has a defined function "values" that returns multiple values using continuations, a way it can be implemented is shown in "my-values" ```Racket #lang racket (values 4 5) (define (my-values . return-list) (call/cc (lambda (return) (apply return return-list)))) ``` ## Raven ```Raven define multiReturn use $v $v each 3 multiReturn ``` {{out}} ```txt 2 1 0 ``` ## Retro Functions take and return values via a stack. This makes returning multiple values easy. ```Retro : addSubtract ( xy-nm ) 2over - [ + ] dip ; ``` ## REXX Strictly speaking, REXX only returns one value (or no values), but the value (a string) can comprise of multiple "values" or substrings. If the multiple values are separated by blanks [or some other unique character(s) such as a comma, semicolon, backslash, ...], it's a very simple matter to parse the multiple-value string into the desired substrings (or values, if you will) with REXX's handy-dandy '''parse''' statement. ```REXX /*REXX program shows and displays examples of multiple RETURN values from a function.*/ numeric digits 70 /*the default is: NUMERIC DIGITS 9 */ parse arg a b . /*obtain two numbers from command line.*/ if a=='' | a=="," then a= 82 /*Not specified? Then use the default.*/ if b=='' | b=="," then b= 20 /* " " " " " " */ say ' a =' a /*display the first number to the term.*/ say ' b =' b /* " " second " " " " */ say copies('═', 50) /*display a separator line " " " */ z= arithmetics(a, b) /*call the function: arithmetics */ parse var z abut sum diff rem div Idiv prod pow /*obtain the function's returned values*/ say ' || =' abut /*display abutment to the terminal.*/ say ' + =' sum /* " sum " " " */ say ' - =' diff /* " difference " " " */ say ' // =' rem /* " remainder " " " */ say ' / =' div /* " quotient " " " */ say ' % =' Idiv /* " int. quotient " " " */ say ' * =' prod /* " product " " " */ say ' ** =' pow /* " power " " " */ exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ arithmetics: procedure; parse arg x,y; return x||y x+y x-y x//y x/y x%y x*y x**y ``` {{out|output|text= when using the default inputs:}} ```txt a = 82 b = 20 ══════════════════════════════════════════════════ || = 8220 + = 102 - = 62 // = 2 / = 4.1 % = 4 * = 1640 ** = 188919613181312032574569023867244773376 ``` ## Ring ```ring Func AddSub x,y Return [ x+y, x-y ] ``` ## Ruby Every function returns one value. The conventional way to return multiple values is to bundle them into an Array. Use an array literal: ```ruby def addsub(x, y) [x + y, x - y] end ``` Or use return with 2 or more values: ```ruby def addsub(x, y) return x + y, x - y end ``` (With at least 2 values, return makes a new Array. With 1 value, return passes the value, without making any Array. With 0 values, return passes nil.) Assignment can split the Array into separate variables. ```ruby sum, difference = addsub(33, 12) puts "33 + 12 = #{sum}" puts "33 - 12 = #{difference}" ``` ## Run BASIC Courtesy http://dkokenge.com/rbp Gets the UTC time from the web ```runbasic a$ = timeInfo$() print " UTC:";word$(a$,1,"|") print "Date:";word$(a$,2,"|") print "Time:";word$(a$,3,"|") wait function timeInfo$() utc$ = word$(word$(httpget$("http://tycho.usno.navy.mil/cgi-bin/timer.pl"),1,"UTC"),2,"
") ' Universal time d$ = date$() t$ = time$() timeInfo$ = utc$;"|";d$;"|";t$ end function ``` ## Rust Rust supports ADT, thus function can return tuple. ```rust fn multi_hello() -> (&'static str, i32) { ("Hello",42) } fn main() { let (str,num)=multi_hello(); println!("{},{}",str,num); } ``` {{out}} ```txt Hello,42 ``` ## Scala Every function returns one value. The conventional way to return multiple values is to return a tuple. ```scala def addSubMult(x: Int, y: Int) = (x + y, x - y, x * y) ``` A more detailed declaration would be: ```scala def addSubMult(x: Int, y:Int) : (Int, Int, Int) = { ... (x + y, x - y, x * y) } ``` You can use pattern matching to extract the components: ```scala val (sum, difference) = addsub(33, 12) ``` Scala borrows this idea from ML, and generalizes it into [http://www.scala-lang.org/node/112 extractors]. ## Scheme Scheme can return multiple values using the values function, which uses continuations: ```scheme (define (addsub x y) (values (+ x y) (- x y))) ``` You can use the multiple values using the call-with-values function: ```scheme (call-with-values (lambda () (addsub 33 12)) (lambda (sum difference) (display "33 + 12 = ") (display sum) (newline) (display "33 - 12 = ") (display difference) (newline))) ``` The syntax is kinda awkward. SRFI 8 introduces a receive construct to make this simpler: ```scheme (receive (sum difference) (addsub 33 12) ; in this scope you can use sum and difference (display "33 + 12 = ") (display sum) (newline) (display "33 - 12 = ") (display difference) (newline)) ``` SRFI 11 introduces a let-values construct to make this simpler: ```scheme (let-values (((sum difference) (addsub 33 12))) ; in this scope you can use sum and difference (display "33 + 12 = ") (display sum) (newline) (display "33 - 12 = ") (display difference) (newline)) ``` ## Seed7 Seed7 functions can only return one value. That value could be an array or record holding multiple values, but the usual method for returning several values is using a procedure with [http://seed7.sourceforge.net/manual/params.htm#inout_parameter inout] parameters: ```Seed7 $ include "seed7_05.s7i"; const proc: sumAndDiff (in integer: x, in integer: y, inout integer: sum, inout integer: diff) is func begin sum := x + y; diff := x - y; end func; const proc: main is func local var integer: sum is 0; var integer: diff is 0; begin sumAndDiff(5, 3, sum, diff); writeln("Sum: " <& sum); writeln("Diff: " <& diff); end func; ``` {{out}} ```txt Sum: 8 Diff: 2 ``` ## Sidef ```ruby func foo(a,b) { return (a+b, a*b); } ``` Catching the returned arguments: ```ruby var (x, y) = foo(4, 5); say x; #=> 9 say y; #=> 20 ``` ## Smalltalk Smalltalk returns a single value from methods, so this task is usually implemented the scheme-way, by passing a lambda-closure which is invoked with the values to return and either operates on the values itself or sets them as the caller's locals (i.e. simular to call-with-values ... values): ```smalltalk foo multipleValuesInto:[:a :b | Transcript show:a; cr. Transcript show:b; cr. ] ``` or: ```smalltalk |val1 val2| foo multipleValuesInto:[:a :b | val1 := a. val2 := b. ]. ... do something with val1 and val2... ``` The called method in foo looks like: ```smalltalk multipleValuesInto: aTwoArgBlock ... aTwoArgBlock value: value: ``` i.e. it invokes the passed-in lambda closure with the two (return-)values. ## Standard ML Every function returns one value. The conventional way to return multiple values is to return a tuple. ```sml fun addsub (x, y) = (x + y, x - y) ``` You can use pattern matching to extract the components: ```sml let val (sum, difference) = addsub (33, 12) in print ("33 + 12 = " ^ Int.toString sum ^ "\n"); print ("33 - 12 = " ^ Int.toString difference ^ "\n") end ``` ## Swift Every function returns one value. The conventional way to return multiple values is to bundle them into a tuple. ```swift func addsub(x: Int, y: Int) -> (Int, Int) { return (x + y, x - y) } ``` You can use pattern matching to extract the components: ```swift let (sum, difference) = addsub(33, 12) println("33 + 12 = \(sum)") println("33 - 12 = \(difference)") ``` ## Tcl Tcl commands all return a single value, but this value can be a compound value such as a list or dictionary. The result value of a procedure is either the value given to the return command or the result of the final command in the body in the procedure. (Commands that return “no” value actually return the empty string.) ```tcl proc addsub {x y} { list [expr {$x+$y}] [expr {$x-$y}] } ``` This can be then assigned to a single variable with set or to multiple variables with lassign. ```tcl lassign [addsub 33 12] sum difference puts "33 + 12 = $sum, 33 - 12 = $difference" ``` ## TXR TXR functions return material by binding unbound variables. The following function potentially returns three values, which will happen if called with three arguments, each of which is an unbound variable: ```txr @(define func (x y z)) @ (bind w "discarded") @ (bind (x y z) ("a" "b" "c")) @(end) ``` The binding w, if created, is discarded because w is not in the list of formal parameters. However, w can cause the function to fail because there can already exist a variable w with a value which doesn't match "discarded". Call: ```txr @(func t r s) ``` If t, r and s are unbound variables, they get bound to "a", "b" and "c", respectively via a renaming mechanism. This may look like C++ reference parameters or Pascal "var" parameters, and can be used that way, but isn't really the same at all. Failed call ("1" doesn't match "a"): ```txr @(func "1" r s) ``` Successful call binding only one new variable: ```txr @(func "a" "b" s) ``` ## UNIX Shell Shell scripts don't directly support returning values from a function, it can be simulated through some clunky code. ```bash #!/bin/sh funct1() { a=$1 b=`expr $a + 1` echo $a $b } values=`funct1 5` set $values x=$1 y=$2 echo "x=$x" echo "y=$y" ``` {{out}} ```txt x=5 y=6 ``` ## Ursa The most straightforward way to return multiple values from a function in Ursa is to return a stream. This example gets a specified amount of strings from the user, then returns a stream containing them. ```ursa def getstrs (int n) decl string<> input while (> n 0) out ": " console append (in string console) input dec n end while return input end getstrs decl int amount out "how many strings do you want to enter? " console set amount (in int console) decl string<> ret set ret (getstrs amount) out endl ret endl console ``` {{out}} ```txt how many strings do you want to enter? 5 : these : are : some : test : strings class java.lang.String ``` ## VBA Firt way : User Defined Type ```vb Type Contact Name As String firstname As String Age As Byte End Type Function SetContact(N As String, Fn As String, A As Byte) As Contact SetContact.Name = N SetContact.firstname = Fn SetContact.Age = A End Function 'For use : Sub Test_SetContact() Dim Cont As Contact Cont = SetContact("SMITH", "John", 23) Debug.Print Cont.Name & " " & Cont.firstname & ", " & Cont.Age & " years old." End Sub ``` {{out}} ```txt SMITH John, 23 years old. ``` Second way : ByRef argument : (Note : the ByRef Arg could be an array) ```vb Function Divide(Dividend As Integer, Divisor As Integer, ByRef Result As Double) As Boolean Divide = True On Error Resume Next Result = Dividend / Divisor If Err <> 0 Then Divide = False On Error GoTo 0 End If End Function 'For use : Sub test_Divide() Dim R As Double, Ddd As Integer, Dvs As Integer, B As Boolean Ddd = 10: Dvs = 3 B = Divide(Ddd, Dvs, R) Debug.Print "Divide return : " & B & " Result = " & R Ddd = 10: Dvs = 0 B = Divide(Ddd, Dvs, R) Debug.Print "Divide return : " & B & " Result = " & R End Sub ``` {{out}} ```txt Divide return : True Result = 3,33333333333333 Divide return : False Result = 1,#INF ``` Third way : ParramArray ```vb Function Multiple_Divide(Dividend As Integer, Divisor As Integer, ParamArray numbers() As Variant) As Long Dim i As Integer On Error GoTo ErrorHandler numbers(LBound(numbers)) = Dividend / Divisor For i = LBound(numbers) + 1 To UBound(numbers) numbers(i) = numbers(i - 1) / Divisor Next i Multiple_Divide = 1: Exit Function ErrorHandler: Multiple_Divide = 0 End Function 'For use : Sub test_Multiple_Divide() Dim Arr(3) As Variant, Ddd As Integer, Dvs As Integer, L As Long, i As Integer Ddd = 10: Dvs = 3 L = Multiple_Divide(Ddd, Dvs, Arr(0), Arr(1), Arr(2), Arr(3)) Debug.Print "The function return : " & L Debug.Print "The values in return are : " For i = LBound(Arr) To UBound(Arr) Debug.Print Arr(i) Next i Erase Arr Debug.Print "--------------------------------------" Ddd = 10: Dvs = 0 L = Multiple_Divide(Ddd, Dvs, Arr(0), Arr(1), Arr(2), Arr(3)) Debug.Print "The function return : " & L Debug.Print "The values in return are : " For i = LBound(Arr) To UBound(Arr) Debug.Print IIf(Arr(i) = "", "vbNullString", "Null") Next i End Sub ``` {{out}} ```txt The function return : 1 The values in return are : 3,33333333333333 1,11111111111111 0,37037037037037 0,123456790123457 -------------------------------------- The function return : 0 The values in return are : vbNullString vbNullString vbNullString vbNullString ``` Fourth way : the variant() function ```vb Function List() As String() Dim i&, Temp(9) As String For i = 0 To 9 Temp(i) = "Liste " & i + 1 Next List = Temp End Function 'For use : Sub test_List() Dim myArr() As String, i As Integer 'Note : you don't need to Dim your array ! myArr = List() For i = LBound(myArr) To UBound(myArr) Debug.Print myArr(i) Next End Sub ``` {{out}} ```txt Liste 1 Liste 2 Liste 3 Liste 4 Liste 5 Liste 6 Liste 7 Liste 8 Liste 9 Liste 10 ``` ## Visual FoxPro ```vfp *!* Return multiple values from a function *!* The simplest way is to pass the parameters by reference *!* either by SET UDFPARMS TO REFERENCE, or prefix the variables with @. LOCAL a, b a = 5 b = 6 ? "Sum =", AddUp(@a, @b) && Displays 11 ? "a =", a, "b =", b && Displays 4, 5 ? "Sum =", AddUp(@a, @b) && Displays 9 FUNCTION AddUp(n1, n2) LOCAL n n = n1 + n2 n1 = n1 - 1 n2 = n2 - 1 RETURN n ENDFUNC ``` ## XPL0 ```XPL0 include c:\cxpl\codes; \intrinsic 'code' declarations proc Rect2Polar(X,Y,A,D); \Return two polar coordinate values real X,Y,A,D; [A(0):= ATan2(Y,X); D(0):= Sqrt(X*X+Y*Y); ]; \Rect2Polar real Ang, Dist; [Rect2Polar(4.0, 3.0, @Ang, @Dist); \("@" is a new feature similar to 'addr') RlOut(0, Ang); RlOut(0, Dist); CrLf(0); ] ``` {{out}} (angle is in radians): ```txt 0.64350 5.00000 ``` ## zkl ```zkl fcn f{return(1,2,"three")} a,b,c:=f() // a==1, b==2, c=="three" ```