C++第十二周【任务4】类的组合与继承

/** 程序的版权和版本声明部分* Copyright (c) 2011, 烟台大学计算机学院学生 * All rights reserved.* 文件名称：C++第十二周【任务4】                              * 作    者：   李洪悬                              * 完成日期：   2012  年  5  月  8  日

* 对任务及求解方法的描述部分* 输入描述：圆的基本数据

* 问题描述：类的组合与继承

* 程序输出：圆的各种信息

*/

【任务4】类的组合与继承（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，派生出一个Circle(圆)类，增加数据成员(半径)，基类的成员表示圆心；（3）编写上述两类中的构造、析构函数及必要的输入输出函数（4）定义友元函数int locate，判断点p在圆c上、圆c内或圆c外，返回值<0圆内，==0圆上，>0 圆外；（5）重载关系运算符（6种）运算符，使之能够按圆的面积比较两个圆的大小；（6）给定一点p，求出该点与圆心相连成的直线与圆的两个交点并输出

BB平台的代码：

//用下面的main()函数测试

int main( ){Circle c1(3,2,4),c2(4,5,5);      //c2应该大于c1Point 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<<endl; cout<<"圆c1: "<<c1;if(c1>c2) cout<<"大于"<<endl;if(c1<c2) cout<<"小于"<<endl; if(c1>=c2) cout<<"大于等于"<<endl;if(c1<=c2) cout<<"小于等于"<<endl; if(c1==c2) cout<<"等于"<<endl; if(c1!=c2) cout<<"不等于"<<endl; cout<<"圆c2: "<<c1;cout<<endl; Point p4,p5;crossover_point1(p1,c1, p4, p5);cout<<"点p1: "<<p1;cout<<"与圆c1: "<<c1;cout<<"的圆心相连，与圆交于两点，分别是："<<endl;cout<<"交点: "<<p4;cout<<"交点: "<<p5;cout<<endl; system("pause");return 0;}

 

程序源代码：

#include<iostream>#include<Cmath>using namespace std;const double pi=3.14;        class Point //定义坐标点类       {      public:          Point(){x=0;y=0;}          Point(double x0,double y0){x=x0;y=y0;}           double get_x(){return x;}          double get_y(){return y;}          void set_x(double n){ x=n;}          void set_y(double n){y=n;}          friend ostream &operator << (ostream & output, Point & c);       private:     double x,y;   //点的横坐标和纵坐标       };       ostream &operator << (ostream & output, Point & c)    {        output<<"该点的横坐标为："<<c.x<<"    "<<"纵坐标为："<<c.y<<endl;    return output;      }    class Circle: public Point   //利用坐标点类定义圆类, 其基类的数据成员表示圆的中心       {      public:          Circle(double xx,double yy,double dd): Point(xx,yy) ,d(dd){}//构造函数                 friend ostream &operator << (ostream & output, Circle & c);    friend double locate(Point &,Circle &);        friend void crossover_point1(Point &p1,Circle &c1,Point &p4,Point &p5);           bool operator > (Circle &t);            bool operator < (Circle &t);            bool operator >= (Circle &t);            bool operator <= (Circle &t);            bool operator == (Circle &t);            bool operator != (Circle &t);        private:     double d;      };     void crossover_point1(Point &p1,Circle &c1,Point &p4,Point &p5)    {        double n;        n=c1.get_x()+(sqrt((p1.get_x()-c1.get_x())*(p1.get_x()-c1.get_x ()))*c1.d )/(sqrt((p1.get_x ()-c1.get_x ())*(p1.get_x ()-c1.get_x ())+((p1.get_y ()-c1.get_y ())*(p1.get_y ()-c1.get_y ()))));        p4.set_x (n);        n=c1.get_x ()-(sqrt((p1.get_x ()-c1.get_x ())*(p1.get_x ()-c1.get_x ()))*c1.d )/(sqrt((p1.get_x ()-c1.get_x ())*(p1.get_x ()-c1.get_x ())+((p1.get_y ()-c1.get_y ())*(p1.get_y ()-c1.get_y ()))));        p5.set_x (n);        n=c1.get_y ()+(sqrt((p1.get_y ()-c1.get_y ())*(p1.get_y ()-c1.get_y ()))*c1.d )/(sqrt((p1.get_x ()-c1.get_x ())*(p1.get_x ()-c1.get_x ())+((p1.get_y ()-c1.get_y ())*(p1.get_y ()-c1.get_y ()))));        p4.set_y (n);        n=c1.get_y ()-(sqrt((p1.get_y ()-c1.get_y ())*(p1.get_y ()-c1.get_y ()))*c1.d )/(sqrt((p1.get_x ()-c1.get_x ())*(p1.get_x ()-c1.get_x ())+((p1.get_y ()-c1.get_y ())*(p1.get_y ()-c1.get_y ()))));        p5.set_y (n);    }    ostream &operator << (ostream & output, Circle & c)    {        output<<"圆的半径为："<<c.d<<"圆的圆心为"<<"("<<c.get_x()<<","<<c.get_y()<<")"<<endl;            return output;        }      double locate(Point &p,Circle &c)    {        double s,d,m;        s=(c.get_x()-p.get_x () )*(c.get_x()-p.get_x () )+(c.get_y ()-p.get_y () )*(c.get_y ()-p.get_y () );        m=sqrt(s);        d=m-c.d ;        return d;    }    bool Circle::operator > (Circle &t)      {            double s1,s2;        s1=pi*d*d;        s2=pi*t.d*t.d;        if(s1>s2 )              return true;          else              return false;      }      bool Circle::operator < (Circle &t)       {          double s1,s2;        s1=pi*d*d;        s2=pi*t.d*t.d;        if(s1<s2 )               return true;          else              return false;      }      bool Circle::operator >= (Circle &t)      {            double s1,s2;        s1=pi*d*d;        s2=pi*t.d*t.d;         if (s1<s2)                return false;            return true;        }            bool Circle::operator <= (Circle &t)      {            double s1,s2;        s1=pi*d*d;        s2=pi*t.d*t.d;         if (s1>s2)                return false;            return true;        }        bool Circle::operator == (Circle &t)       {          double s1,s2;        s1=pi*d*d;        s2=pi*t.d*t.d;         if (s1<s2)                return false;            if (s1>s2)                return false;            return false;      }          bool Circle::operator != (Circle &t)      {          double s1,s2;        s1=pi*d*d;        s2=pi*t.d*t.d;         if (s1==s2)                return false;          return true;      }      int main( ){Circle c1(3,2,4),c2(4,5,5);      //c2应该大于c1Point 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<<endl; cout<<"圆c1: "<<c1;if(c1>c2) cout<<"大于"<<endl;if(c1<c2) cout<<"小于"<<endl; if(c1>=c2) cout<<"大于等于"<<endl;if(c1<=c2) cout<<"小于等于"<<endl; if(c1==c2) cout<<"等于"<<endl; if(c1!=c2) cout<<"不等于"<<endl; cout<<"圆c2: "<<c1;cout<<endl; Point p4,p5;crossover_point1(p1,c1, p4, p5);cout<<"点p1: "<<p1;cout<<"与圆c1: "<<c1;cout<<"的圆心相连，与圆交于两点，分别是："<<endl;cout<<"交点: "<<p4;cout<<"交点: "<<p5;cout<<endl; system("pause");return 0;}

运行结果：

圆c1: 圆的半径为：4圆的圆心为(3,2)
点p1: 该点的横坐标为：1    纵坐标为：1
点p1在圆c1之内
点p2: 该点的横坐标为：3    纵坐标为：-2
点p2在圆c1之上
点p3: 该点的横坐标为：7    纵坐标为：3
点p3在圆c1之外

圆c1: 圆的半径为：4圆的圆心为(3,2)
小于
小于等于
不等于
圆c2: 圆的半径为：4圆的圆心为(3,2)

点p1: 该点的横坐标为：1    纵坐标为：1
与圆c1: 圆的半径为：4圆的圆心为(3,2)
的圆心相连，与圆交于两点，分别是：
交点: 该点的横坐标为：6.57771    纵坐标为：3.78885
交点: 该点的横坐标为：-0.577709    纵坐标为：0.211146

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