不使用第三个变量来交换连个数据

#include <iostream>

using namespace std;

int a = 3;

int b = 4;

//a = a ^ b;
//b = a ^ b;
//a = a ^ b;

a = a + b;
b = a - b;  
a = a - b ;  

cout << a <<endl;
cout << b << endl;