#include <stdio.h>

void swap(int *x, int *y);


int main(int argc, char *argv[]) {
	int x = -419;
	int y = 172;
	printf("Before swap :  x = %4d    y = %4d\n", x, y);
	swap(&x, &y);
	printf("After swap  :  x = %4d    y = %4d\n", x, y);
	return 0;
}

/*
 * Swap values pointed to by x and y
 */
void swap(int *x, int *y) {
	*x ^= *y;
	*y ^= *x;
	*x ^= *y;
}