#include <stdio.h>
int main() {
  int a = 314;
  int *p, *q;
  p = q = &a; 
  printf("%d,%d\n", *p, *q);
  *p ^= *q;
  *q ^= *p;
  *p ^= *q;
  printf("%d,%d\n", *p, *q);
  return 0;
}

314,314
0,0