交换变量

first:

int exchange_ab(int* a , int* b){    int t = *a;    *a = *b;    *b = t;}

second:

int exchange_ab(int* a, int* b){    *a = (*a)^(*b);    *b = (*a)^(*b);    *a = (*a)^(*b);}

three:

int exchange_ab(int* a, int* b){    *a = *a+*b;    *b = *a-*b;    *a = *a-*b;}

完整代码：

#include <iostream>#include <cstdio>using namespace std;int main(){    int a , b ;    while(cin >> a >> b)    {        exchange_ab(&a , &b);        cout << a <<" "<< b << endl;    }    return 0;}