Write a Program in C to Swap the values of two variables without using any extra variable.

swap.c

#include <stdio.h>

int main() {
    int a = 123123123;
    int b = 456456456;

    printf("before swap: a = %d b = %d\n", a, b);

    // other swap options:

    // asm xchg (only x86)
    // asm 3 movs (non-atomic)
    // arithmetic (xor, +/-, mul/div etc) (non-atomic)

    __asm__ (
        "mov %w2, %w0\n" // w2=w0 - use extra registry to backup w0 value
        "mov %w0, %w1\n" // w0=w1
        "mov %w1, %w2\n" // w1=w2
        : "+r" (a), "+r" (b) // put a into %w0 and b into %w1
    );

    printf("after swap: a = %d b = %d\n", a, b);
}