【C++】指针，引用，值传递函数参数

#include <iostream>

using namespace std;

void swapr(int &a,int &b);
void swapp(int *pa,int *pb);
void swapv(int a,int b);
int main()
{
    int wallet1=300;
    int wallet2=350;

    cout << "wallet1 = "<<wallet1<<endl;
    cout << "wallet2 = "<<wallet2<<endl;

    cout << "Using reference to swap contents:" << endl;
    swapr(wallet1,wallet2);
    cout << "wallet1 = "<<wallet1<<endl;
    cout << "wallet2 = "<<wallet2<<endl;


    cout << "Using pointers to swap contents:" << endl;
    swapp(&wallet1,&wallet2);
    cout << "wallet1 = "<<wallet1<<endl;
    cout << "wallet2 = "<<wallet2<<endl;

    cout << "Using pointers to swap contents:" << endl;
    swapv(wallet1,wallet2);
    cout << "wallet1 = "<<wallet1<<endl;
    cout << "wallet2 = "<<wallet2<<endl;

    return 0;


}

void swapr(int &a,int &b)
{
    int temp;
    temp = a;
    a = b;
    b = temp;
}

void swapp(int *pa,int *pb)
{
    int temp;
    temp = *pa;
    *pa = *pb;
    *pb = temp;
}

void swapv(int a,int b)
{
    int temp;
    temp = a ;
    a = b;
    b = temp;
}

引用和指针都可以改变原调用函数的实参值，值传递不可以。