引用的基础知识

#include<iostream>
using namespace std;
//1 引用的概念
//2 属于C++编译器对C的扩展，不能用C语言的语法去思考它
void main1()
{
    int  a = 10;
    //引用的语法：Type& name=var；
    int &b = a;//b是a的别名，可通过b操作a
    b = 100;//相当于把a修改成了100了
    printf("b:%d
", b);
    printf("a:%d
", a);
    a = 200;
    printf("b:%d
", b);
    printf("a:%d
", a);
    system("pause");
    return;
}
//3 普通引用必须要初始化
void main2()
{
    int a = 10;
    int &b = a;
    //int &c; 
    system("pause");
}

//基础类型的引用
void myswap(int a, int b)
{
    int c;
    c = a;
    a = b;
    b = c;
}

void myswap2(int *a, int *b)
{
    int c;
    c = *a;
    *a = *b;
    *b = c;
}

//4 引用作为函数参数声明时不进行初始化
void myswap3(int &a, int &b)
{
    int c;
    c = a;
    a = b;
    b = c;
}

void main()
{
    int x, y;
    x = 10;
    y = 20;
    myswap(x, y);
    printf("x:%d,y:%d
", x, y);

    myswap2(&x, &y);
    printf("x:%d,y:%d
", x, y);

    //a就是x的别名，b就是y的别名
    myswap3(x, y);
    printf("x:%d,y:%d
", x, y);

    system("pause");
}