int main()
{
  int a = 1;
  int b = 3;
  a = a^b;
  b = a^b;
  a = a^b;
  printf("a = %d\n", a);
  printf("b = %d\n", b);
  return 0;
}

上述代码实现了不创建临时变量实现a，b值的交换，这里注意^操作符的使用
记住这个规律：a^a = 0, 0^a = a
因此 a^b^a = b, a^b^b = a
^操作满足交换律