程序代码：

#include<iostream>
using namespace std;

void swap(int &a,int &b);

main()
{
    
    int r = 5, t = 6;
    swap(r,t);
    cout<<"r:"<<r<<" t:"<<t<<endl;
}
void swap(int &a,int &b)
{
    int temp = a;
    a = b;
    b = temp;
}

程序代码：

#include<iostream>
using namespace std;

main()
{
    void swap(int &a,int &b);
    int r = 5, t = 6;
    swap(r,t);
    cout<<"r:"<<r<<" t:"<<t<<endl;
}
void swap(int &a,int &b)
{
    int temp = a;
    a = b;
    b = temp;
}