引用作为函数参数

函数传参的实质是函数在栈区创建了(临时的)局部变量，接受传过来的数据

#include <iostream>
using namespace std;

void swap(int&,int&);

int main(int argc, const char * argv[]) {
    int a =10, b =100;
    cout<<"before swap --- a:"<<a <<" b:"<<b<<endl;
    swap(a,b);
    cout<<"after swap --- a:"<<a <<" b:"<<b<<endl;
    return 0;
}

void swap(int& rx,int& ry)
{
    int temp;
    temp = rx;
    rx = ry;
    ry =temp;
}

before swap --- a:10 b:100
after swap --- a:100 b:10