Xor swap

Swapping two variables normally implies that you have to use a third temporary variable as a buffer. But this prove of concept code shows that this can be done without a third variable using the XOR operator.

But you ask yourself what that code is good for?

In cases you don't have much RAM but much FLASH ROM for program code.
If you have very big values... have you?

The code

Swap variable a and b with xor operation:

int main() {
    int a=123;
    int b=23;
    printf("%i %i\n", a, b);
    a = a ^ b;
    b = a ^ b;
    a = a ^ b;
   printf("%i %i\n", a, b); 
}

Cmd output

joachim@flixflux:/tmp
15 $ ./xor_swap
123 23
23 123