形参引用类型_而传入的实参随便时

/*
如下，函数的形参是引用类型，如果把一个不设定为引用类型的参数传进去，效果入下。
基本如预料。
*/
#include <iostream>
using namespace std;

void func(int& i)
{
    i = 1;
}

void main()
{
    int x = 9;
    cout<<"before:\t"<<x<<endl;
    func(x);
    cout<<"after:\t"<<x<<endl;
    system("pause");
}
/*
output:
before:9
after:1
*/

#include <iostream>
using namespace std;

void func(int& i)
{
    i = 1;
}

void main()
{
    int y = 9;
    int& x = y;
    cout<<"before:\t"<<x<<","<<y<<endl;
    func(x);
    cout<<"after:\t"<<x<<","<<y<<endl;
    system("pause");
}
/*
output:
before:9,9
after:1,1
*/

#include <iostream>
using namespace std;

void func(int& i)
{
    i = 1;
}

void func1(int i)
{
    i = 2;
}

void main()
{
    int y = 9;
    int& x = y;
    cout<<"before:\t"<<x<<","<<y<<endl;
    //func(x);
    func1(x);
    cout<<"after:\t"<<x<<","<<y<<endl;
    system("pause");
}
/*
output:
before:9,9
after:9,9
*/

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哎，理解不够，放几个例子对比吧。