3-7 类的友元函数的应用

3-7 类的友元函数的应用

Time Limit: 1000MS Memory Limit: 65536KB

Submit Statistic

Problem Description

通过本题目的练习可以掌握类的友元函数的定义和用法

要求设计一个点类Point，它具有两个double型的数据成员x，y。为该类设计构造函数。并为其添加一个友元函数用于计算并输出两点间的距离；再添加一个输出成员函数用于输出点的信息。

 

 

并编写主函数，实现以下的输入输出内容。

Input

4个double型的数，中间用一个空格间隔。

Output

输出数据共3行，前两行用于显示要求距离的两个点的信息，第三行显示两点的距离。

Example Input

5 6 2 3

Example Output

The first point is the coordinate:X=5,Y=6The second point is the coordinate:X=2,Y=3The distance between the two points is:4.24264

#include<bits/stdc++.h>using namespace std;class Point{public :    Point (double a=0,double b=0)    {        x=a;        y=b;    }    friend void dis(Point &p1,Point &p2);    void show()    {        cout<<"The first point is the coordinate:X="<<x<<","<<"Y="<<y<<endl;    }    void show1()    {        cout<<"The second point is the coordinate:X="<<x<<","<<"Y="<<y<<endl;    }private:   double x,y;};void dis(Point &p1,Point &p2){    double x=p1.x-p2.x;    double y=p1.y-p2.y;    double t= sqrt(x*x+y*y);    cout<<"The distance between the two points is:"<<t<<endl;}int main(){    double x1,x2,x3,x4;    cin>>x1>>x2>>x3>>x4;    Point p1(x1,x2);    Point p2(x3,x4);    p1.show();    p2.show1();    dis(p1,p2);    return 0;}