c/c++(const)(5)

函数参数传递

一，按值传递

#include<iostream>

using namespace std;

void swap(int x ,int y);

int main()
{
     int x=5;y=10;
     cout<<"main before swap,x:"<<x<<"y:"<<y<<endls;
     swap(x,y);
     cout<<"main after swap,x:"<<x<<"y:"<<y<<endls;
     retuen 0;
}

void swap(int x,int y)
{
     int tmp;
     cout<<"swap before swap,x:"<<x<<"y:"<<y<<endls;
     temp=x;
     x=y;
     y=temp;
     cout<<"swap  before swap,x:"<<x<<"y:"<<y<<endls;
}

二,按指针传递

#include<iostream>

using namespace std;

void swap(int *x ,int *y);

int main()
{
     int x=5;y=10;
     cout<<"main before swap,x:"<<x<<"y:"<<y<<endls;
     swap(&x,&y);
     cout<<"main after swap,x:"<<x<<"y:"<<y<<endls;
     retuen 0;
}

void swap(int *px,int *py)
{
     int tmp;
     cout<<"swap before swap,*px:"<<px<<"*py:"<<py<<endls;
     temp=*px;
     *px=*py;
     *py=temp;
     cout<<"swap  before swap,*px:"<<*px<<"*py:"<<py<<endls;
}

三,引用传递参数

#include<iostream>

using namespace std;

void swap(int &x ,int &y);

int main()
{
     int x=5;y=10;
     cout<<"main before swap,x:"<<x<<"y:"<<y<<endls;
     swap(x,y);
     cout<<"main after swap,x:"<<x<<"y:"<<y<<endls;
     retuen 0;
}

void swap(int &rx,int  &ry)
{
     int tmp;
     cout<<"swap before swap,rx:"<<rx<<"ry:"<<ry<<endls;
     temp=rx;
     rx=ry;
     ry=temp;
     cout<<"swap  before swap,rx:"<<rx<<"ry:"<<ry<<endls;
}