3.引用做函数参数

#include<iostream>
using namespace std;
//函数传参时，可以利用引用让形参修改实参，可以简化指针修改实参
//交换函数
//1.值传递
void swap1(int a,int b)
{
    int m = a;
    a = b;
    b = m;
    cout << "函数内a=" << a << endl;
    cout << "函数内b=" << b << endl;
}

//2.地址传递
void swap2(int* a, int* b)
{
    int m = *a;
    *a = *b;
    *b = m;
}
//3.引用传递
void swap3(int& a, int& b)
{
    int m = a;
    a = b;
    b = m;
}
int main()
{
    int a = 1;
    int b = 2;
    /*值传递
    swap1(a, b);
    cout << "a=" << a << endl;
    cout << "b=" << b << endl;
    */

    /*地址
    swap2(&a, &b);
    cout << "a=" << a << endl;
    cout << "b=" << b << endl;
    */
    //引用，实参是形参的别名，对形参的修改相当于对实参的修改
    swap3(a, b);
    cout << "a=" << a << endl;
    cout << "b=" << b << endl;
    
    system("pause");
    return 0;
}