第十三周上机实践项目——圆的比较

/*
*程序的版权和版本声明部分：
*Copyright(c)2014，烟台大学计算机学院学生
*All rights reserved.
*文件名称：圆的比较
*作者：刘中林
*完成日期：2014 年 5 月 20 日
*版本号：v1.0
*对任务及求解方法的描述部分：
*输入描述: -
*问题描述： (1)先建立一个Point(点)类，包含数据成员x,y(坐标点)；
(2)以Point为基类，派生一个Circle(圆)类，增加数据成员(半径)，基类成员表示圆心；
(3)编写上述两类中的构造、析构函数及必要运算符重载函数（本项目主要是输入输出）；
(4)定义友元函数，判断点p与圆的位置关系（返回值<0圆内，==0圆上，>0 圆外）；
在Circle类上重载关系运算符（6种），使之能够按圆的面积比较两个圆的面积的大小。
*程序输出：点与圆的关系
*问题分析：
*算法设计：
*/
#include <iostream>
#include <cmath>
using namespace std;
const double cp=3.14;
class Point
{
public:
friend ostream&operator<<(ostream& output,Point&p);
Point(double x1,double y1):x(x1),y(y1) {}
~Point() {}
double get_x()
{
return x;
}
double get_y()
{
return y;
}
protected:
double x,y;
};
ostream&operator<<(ostream& output,Point& p)
{
output<<"("<<p.get_x()<<","<<p.get_y()<<")"<<endl;
return output;
}
class Circle:public Point
{
public:
double area();
bool operator > (Circle &c);
bool operator < (Circle &c);
bool operator >= (Circle &c);
bool operator <= (Circle &c);
bool operator == (Circle &c);
bool operator != (Circle &c);
friend int locate(Point,Circle);
friend ostream&operator<<(ostream& output,Circle& c);
Circle(double x,double y,double z):Point(x,y),r(z) {}
~Circle() {}
double get_r()
{
return r;
}
protected:
double r;
};
ostream&operator<<(ostream& output,Circle& c)
{
output<<"("<<c.get_x()<<","<<c.get_y()<<")"<<endl;
output<<"r="<<c.get_r()<<endl;
return output;
}
int locate(Point p,Circle c)
{
double R,result;
R=sqrt(pow(p.get_x()-c.get_x(),2)+pow(p.get_y()-c.get_y(),2));
if(R<c.get_r())
{
result=-1;//-1代表<0
}
if(R==c.get_r())
{
result=0;
}
else
{
result=1;
}
return result;
}
double Circle::area()
{
return cp*pow(get_r(),2);
}
bool Circle::operator > (Circle &c)
{
if(area()>c.area())
{
return true;
}
else
{
return false;
}
}
bool Circle::operator < (Circle &c)
{
if(area()<c.area())
{
return true;
}
else
{
return false;
}
}
bool Circle::operator >= (Circle &c)
{
if(!(area()<c.area()))
{
return true;
}
else
{
return false;
}
}
bool Circle::operator <= (Circle &c)
{
if(!(area()>c.area()))
{
return true;
}
else
{
return false;
}
}
bool Circle::operator == (Circle &c)
{
if(area()==c.area())
{
return true;
}
else
{
return false;
}
}
bool Circle::operator != (Circle &c)
{
if(!(area()==c.area()))
{
return true;
}
else
{
return false;
}
}
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;
cout<<"圆c2: "<<c2;
if(c1>c2)
cout<<"c1>c2"<<endl;
if(c1<c2)
cout<<"c1<c2"<<endl;
if(c1==c2)
cout<<"c1=c2"<<endl;
if(c1!=c2)
cout<<"c1!=c2"<<endl;
if(c1>=c2)
cout<<"c1>=c2"<<endl;
if(c1<=c2)
cout<<"c1<=c2"<<endl;
return 0;
}