第十二周项目4——(4)_ostream& operator << (ostream &out const point& p)-优快云博客

本文介绍了一个使用C++实现的点类Point和派生圆类Circle的示例。通过这两个类，可以输出点和圆的基本信息，并判断点与圆之间的位置关系（点在圆内、圆上还是圆外）。此示例展示了如何利用面向对象编程来解决几何问题。

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/*
*Copyright (c) 2014,烟台大学计算机学院void change(int a[8][8]);
*All rights reserved.
*文件名称:main.cpp
*作者:苏强
*完成日期:2015年5月25日
*版本号:v1.0
*
*问题描述:建立点类Point和派生圆类circle，输出点和圆的基本信息并判断点与圆的关系
*/
#include <iostream>
#include<cmath>
using namespace std;
class Point
{
protected:
    double x,y;
public:
    Point(double X,double Y):x(X),y(Y){}
    ~Point(){}
    friend ostream &operator <<(ostream &out,Point &p);
    double distance(Point &p)const;
};
ostream &operator <<(ostream &out,Point &p)
{
    out<<"("<<p.x<<","<<p.y<<")"<<endl;
    return out;
}
double Point::distance(Point &p) const
{
    double dx=x-p.x,dy=y-p.y;
    return sqrt(dx*dx+dy*dy);

}
class Circle:virtual public Point
{
protected:
    double r;
public:
    Circle(double X,double Y ,double R):Point(X,Y),r(R){}
    ~Circle(){}
    friend ostream &operator <<(ostream &out,Circle &c);
    friend int locate(const Point &p,const Circle &c);
};
ostream &operator <<(ostream &out,Circle &c)
{
    out<<"圆心：("<<c.x<<","<<c.y<<")   半径："<<c.r<<endl;
    return out;
}
int locate(const Point &p,const Circle &c)
{
    Point p1(c.x,c.y);
    if(p.distance(p1)==c.r)
        return 0;
    else if(p.distance(p1)>c.r)
        return 1;
    else    return -1;
}
int main( )
{
	Circle c1(3,2,4),c2(4,5,5);      //c2应该大于c1
	Point p1(1,1),p2(3,-2),p3(7,3);  //分别位于c1内、上、外


	cout<<"圆c1: "<<c1;

	cout<<"点p1: "<<p1;
	cout<<"点p1在圆c1之"<<((locate(p1, c1)>0)?"外":((locate(p1, c1)<0)?"内":"上"))<<endl;

	cout<<"点p2: "<<p2;
	cout<<"点p2在圆c1之"<<((locate(p2, c1)>0)?"外":((locate(p2, c1)<0)?"内":"上"))<<endl;

	cout<<"点p3: "<<p3;
	cout<<"点p3在圆c1之"<<((locate(p3, c1)>0)?"外":((locate(p3, c1)<0)?"内":"上"))<<endl;
	return 0;
}