代码如下：

#include <iostream>

using std::cout;
using std::endl;
using std::cin;

void swap(int &n1,int &n2)
{
    n1 = n1 + n2;
    n2 = n1 - n2;
    n1 = n1 - n2;
}

int main()
{
    int n1,n2;
    cout << "请分别输入n1,n2的值：";
    cin >> n1 >> n2;
    swap(n1,n2);
    cout << "交换后的两数分别为：n1 = " << n1 << " , n2 = " << n2 << endl;

    return 0;
}

运行结果：

PS D:\LeetCode> cd "d:\LeetCode\" ; if ($?) { g++ Q22.cpp -o Q22 } ; if ($?) { .\Q22 }
请分别输入n1,n2的值：1 2
交换后的两数分别为：n1 = 2 , n2 = 1