#include<iostream>using namespace std;void swap(int ,int );//两个参数变量可以省略int main(){int x=3,y=4;cout<<"在main函数中,调用swap函数之前,x的值为"<<x<<",y的值为:"<<y<<endl;swap(x,y);cout<<"在main函数中,调用swap函数之后,x的值为"<<x<<",y的值为:"<<y<<endl;return 0;}void swap(int x,int y){cout<<"在swap函数中,调用swap函数之前,x的值为"<<x<<",y的值为:"<<y<<endl;int z;z=x;x=y;y=z;cout<<"在swap函数中,调用swap函数之后,x的值为"<<x<<",y的值为:"<<y<<endl;}运行结果: