sdut 3-7 类的友元函数的应用

题目描写叙述

输入

输出

演示样例输入

5 6 2 3

演示样例输出

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

提示

来源

演示样例程序

#include <iostream>
#include<cmath>

using namespace std;

class point
{
private:
    double x, y;

public:
    //声明display函数为point类的友元函数
    friend void display2(point &t, point &q);
    void display1()
    {
        cout << " point is the coordinate:X=" << x << ',' << "Y=" << y << endl;
    }

    point(double a, double b)
    {
        x = a;
        y = b;
    }
};

void display2(point &t, point &q)//定义友元函数
{
    //使用数学公式求出两点间的距离
    cout << "The distance between the two points is:
        " << sqrt((t.x - q.x) * (t.x - q.x) + (t.y - q.y) * (t.y - q.y)) << endl;
}

int main()
{
    double a, b, c, d;
    cin >> a >> b >> c >> d;
    point x(a,b);
    point y(c,d);
    cout << "The first";
    x.display1();
    cout << "The second";
    y.display1();
    display2(x, y);
    return 0;
}