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Programming-Idioms

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  • Erlang

Idiom #21 Swap values

Swap the values of the variables a and b

fun1(A, B) ->
	do:something(),
	fun2(B, A).

fun2(A, B) ->
	now(A, is, B),
	and(B, is, A),
	keep:moving().

Single assignment precludes you from swapping values in Erlang within the body of a single function.
If you really want the names to change (which you usually don't)… well… you have to move to a different function
procedure swap(a, b: in out Integer)
is
    temp : Integer;
begin
    temp := a;
    a := b;
    b := temp;
end swap;
New implementation...
< > ⌨
programming-idioms.org 
fun1(A, B) ->
	do:something(),
	fun2(B, A).

fun2(A, B) ->
	now(A, is, B),
	and(B, is, A),
	keep:moving().
procedure swap(a, b: in out Integer)
is
    temp : Integer;
begin
    temp := a;
    a := b;
    b := temp;
end swap;
a^=b;
b^=a;
a^=b;

b = a + b
a = b - a
b = b - a
(defn swap [a b]
  [b a])
IDENTIFICATION DIVISION.
PROGRAM-ID. swap.
PROCEDURE DIVISION.
    MOVE a    TO temp
    MOVE b    TO a
    MOVE temp TO b
STOP RUN.
swap(a, b);
var tmp = a;
a = b;
b = tmp;
(a, b) = (b, a);
swap(a,b);
auto temp = a;
a = b;
b = temp;
var tmp = a;
a = b;
b = tmp;
{a, b} = {b, a}
tmp = a
a = b
b = tmp
subroutine swap(a, b)
  integer, intent(inout) :: a, b
  integer :: temp
  temp = a
  a = b
  b = temp
end subroutine swap
a, b = b, a
(a, b) = [b, a]
swap (a,b) = (b,a)

[a, b] = [b, a];
var tmp = a;
a = b;
b = tmp;
T tmp = a;
a = b;
b = tmp;
a = b.also { b = a }
(rotatef a b)
a, b = b, a
__typeof(a) _temp=a; a=b; b=_temp;
[ $b, $a ] = [ $a, $b ];
list($b, $a ) = [ $a, $b ];
$tmp = $a;
$a = $b;
$b = $tmp;
tmp := a;
a := b;
b := tmp;
($a, $b) = ($b, $a);
a, b = b, a
a =int(input("enter a number"))
b =int(input("enter b number")) 
a, b = b, a
 
print("Value of a:", a)
print("Value of a", b)

a, b = b, a
let (a, b) = (b, a);
std::mem::swap(&mut a, &mut b);

val tmp = a
a = b
b = tmp


(define (swap a b)
  (list b a))

[| temp | temp := a. a := b. b := temp] value
Sub Swap(Of T)(ByRef a As T, ByRef b As T)
  Dim tmp as T
  tmp = a
  a = b
  b = tmp 
End Sub