第7周项目1（2） 成员函数，友元函数和一般函数的区别 两点距离类

/* <p><span><span class="comment">02. *Copyright (c) 2016，烟台大学计算机学院</span> </span></p><p class="alt"><span><span class="comment">03. *All rights reserved.</span> </span></p><p><span><span class="comment"> 04. *文件名称：cpp</span> </span></p><p class="alt"><span><span class="comment"> 05. *作    者：孙亚茹</span> </span></p><p><span><span class="comment">06. *完成日期：2016年4月14日</span> </span></p><p class="alt"><span><span class="comment">07. *版 本 号：v1.0</span> </span></p><p><span><span class="comment"> 09. *问题描述：写出三种形式的函数</span> </span></p><p class="alt"><span><span class="comment">*/</span><span>  </span></span></p>

#include <iostream>
#include<cmath>
using namespace std;
class Cpoint
{
public:
    Cpoint(double xx=0,double yy=0):x(xx),y(yy){}
    friend void distance2(Cpoint &x,Cpoint &y);
    void distance3(Cpoint &x,Cpoint &y);
    double getX(){return x;}
    double getY(){return y;}
private:
    double x;
    double y;
};
void distance2(Cpoint &p1,Cpoint&p2)
{
    double d,d1;
    d=(p1.x-p2.x)*(p1.x-p2.x)+(p1.y-p2.y)*(p1.y-p2.y);
    d1=sqrt(d);
    cout<<"两点之间距离为: "<<d1<<endl;
}
 void distance3(Cpoint &p1,Cpoint &p2)
{
    double d,d1;
    d=(p1.getX()-p2.getX())*(p1.getX()-p2.getX())+(p1.getY()-p2.getY())*(p1.getY()-p2.getY());
    d1=sqrt(d);
    cout<<"两点之间距离为: "<<d1<<endl;
}
int main()
{

   Cpoint p1(10,5);
   Cpoint p2(1,6);
   distance2(p1,p2);
   distance3(p1,p2);

    return 0;
}