第十二周 项目4-点，圆的类（2）

/* 
 * Copyright (c) 2014, 烟台大学计算机学院 
 * All rights reserved. 
 * 文件名称：test.cpp 
 * 作    者：呼亚萍 
 * 完成日期：2015年5月27日 
 * 版 本 号：v1.0 
 * 
 * 问题描述: 在圆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大小。
 * 程序输入：相应的程序
 * 程序输出：对应得结果
 */

#include<iostream>
#include<cmath>
using namespace std;
class Point
{
public:
    Point()
    {
        x=0;
        y=0;
    }
    Point(int a,int b):x(a),y(b) {}
    friend ostream& operator<<(ostream&,Point&);
protected:
    double x;
    double y;
};
ostream& operator<<(ostream&output,Point&p)
{
    output<<"("<<p.x<<","<<p.y<<")";
    return output;
}
class Circle:public Point
{
public:
    Circle(double a=0,double b=0,double r=0):Point(a,b),radius(r) {}
    double area();
    friend ostream& operator<<(ostream&,Circle&);
    bool operator>(Circle&);
    bool operator>=(Circle&);
    bool operator<(Circle&);
    bool operator<=(Circle&);
    bool operator==(Circle&);
    bool operator!=(Circle&);
private:
    double radius;
};
ostream& operator<<(ostream&output,Circle&c)
{
    output<<"("<<c.x<<","<<c.y<<")";
    cout<<"r="<<c.radius;
    return output;
}
double Circle::area()
{
    return (3.14*radius*radius);
}
bool Circle::operator>(Circle&c)
{
    if(radius>c.radius)
        return true;
    else
        return false;
}
bool Circle::operator<(Circle&c)
{
    if(radius<c.radius)
        return true;
    else
        return false;
}
bool Circle::operator==(Circle&c)
{
    if(radius==c.radius)
        return true;
    else
        return false;
}
bool Circle::operator>=(Circle&c)
{
    if(radius<c.radius)
        return false;
    else
        return true;
}
bool Circle::operator<=(Circle&c)
{
    if(radius<c.radius)
        return false;
    else
        return true;
}
bool Circle::operator!=(Circle&c)
{
    if(radius==c.radius)
        return false;
    else
        return true;
}
int main( )
{
    Circle c1(3,2,4),c2(4,5,5);      //c2应该大于c1
    cout<<"圆c1( "<<c1<<" )的面积是 "<<c1.area()<<endl;
    cout<<"圆c2( "<<c2<<" )的面积是 "<<c2.area()<<endl;
    cout<<"圆c1 ";
    if(c1>c2) cout<<"大于, ";
    if(c1<c2) cout<<"小于, ";
    if(c1>=c2) cout<<"大于等于, ";
    if(c1<=c2) cout<<"小于等于, ";
    if(c1==c2) cout<<"等于, ";
    if(c1!=c2) cout<<"不等于, ";
    cout<<"圆c2"<<endl;
    return 0;
}

运算结果：

知识点总结：

基类的派生，六种运算符的重载！

学习心得：

程序框架的构建很重要！