C++的引用变量作为函数参数

一、问题引入

在C++的中新增一个特性：按引用传递变量，虽然与按传递变量的地址可以实现相同的结果，但引用有其独特的地方。

引用传递: 引用经常被用作函数参数，使得函数中的变量名成为调用程序中的变量的别名。

通过引用变量用作参数，函数将使用原始数据，而不是其副本。

二、解决过程

举例说明：

#include <iostream>

using namespace std;


void swapv(int a, int b)    // 传变量的值
{
    int temp = a;
    a = b;
    b = temp;
}
void swapp(int *a, int *b)  // 传变量的地址
{
    int temp = *a;
    *a = *b;
    *b= temp;
}
void swapq(int & a, int & b) // 传引用变量
{
    int temp = a;
    a = b;
    b = temp;
}

int main(void)
{
    int wallet1 = 120;
    int wallet2 = 50;
    cout << "source wallet1:" << wallet1 << endl;
    cout << "source wallet2:" << wallet2 << endl;
    cout << endl;

    swapv(wallet1, wallet2);
    cout << "传变量的值" << endl;
    cout << "wallet1:" << wallet1 << endl;
    cout << "wallet2:" << wallet2 << endl;
    cout << endl;

    wallet1 = 120;
    wallet2 = 50;
    swapp(&wallet1, &wallet2);
    cout << "传变量的地址" << endl;
    cout << "wallet1:" << wallet1 << endl;
    cout << "wallet2:" << wallet2 << endl;
    cout << endl;

    wallet1 = 120;
    wallet2 = 50;
    swapq(wallet1, wallet2);
    cout << "传变量" << endl;
    cout << "wallet1:" << wallet1 << endl;
    cout << "wallet2:" << wallet2 << endl;
    cout << endl;

    return 0;
}