交换两个变量的值（不借助第三者）

#include <stdio.h>


int main(void)
{
int a = 4;
int b = 5;


printf("Before change: a = %d\tb = %d\n", a, b);
a ^= b;
b ^= a;
a ^= b;
printf("After change: a = %d\tb = %d\n", a, b);


return 0;
}