/*
   MAT 4370
   Mystery program: yet more bit fiddling

  + What does it do?
  + Can you explain how it works?
  + Can you supply a mathematical proof?
  
*/

#include <stdio.h>

int main(void) {
    int x, y;

    /* Prompt for and obtain two input values */
    printf("Enter two integers: ");
    scanf("%d %d", &x, &y);

    /* Display values before the mystery action */
    printf("BEFORE, x = %d  y = %d\n", x, y);

    /* Perform a mysterious action */
    x ^= y;
    y ^= x;
    x ^= y;

    /* Display values after mystery action */
    printf(" AFTER, x = %d  y = %d\n", x, y);

    return 0;
}