#include <stdio.h>





int main(int argc, char* argv[]) {
    char a = 11;
    char b = 15;
    printf("a = %d, b = %d", a, b);
    *a ^= *b;
    *b ^= *a;
    *a ^= *b;
    printf("a = %d, b = %d", a, b);
    return 0;
}