Swap two numbers without an intermediate variable. Still takes as many statement as with one though…

Explanation!

Swap two numbers without an intermediate variable. Still takes as many statement as with one though…

Consider a = 5, b = 10
a = b0101
b = b1010

a = a ^ b -> b0101 ^ b1010 -> a = b1111 (15)
b = a ^ b -> b1111 ^ b1010 -> b = b0101 (5)
a = a ^ b -> b1111 ^ b0101 -> a = b1010 (10)

a = b1010 = 10
b = b0101 = 5

Values are now swapped. Easy.

swapsie.c

#include <stdio.h>

#define SWAP(a,b) {a = a^b; b = a^b; a = a^b;}

int main(int argc, const char * argv[]) {
    // insert code here...
    int x = 3;
    int y = 298;
    printf("x = %d, y = %d\n", x, y);
    SWAP(x,y);
    printf("x = %d, y = %d\n", x, y);
    return 0;
}