第十周实验报告（3）

【任务3】（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)；

(3）再以Circle类为直接基类，派生出一个Cylinder(圆柱体)类，再增加数据成员h(高)。

要求编写程序，设计出各类中基本的成员函数（包括构造函数、析构函数、修改数据成员和获取数据成员的公共接口、用于输出的重载运算符“<<”函数等），使之能用于处理以上类对象，最后求出圆格柱体的表面积、体积并输出。（提示：此任务可以分为三个子任务分成若干步骤进行。先声明基类，再声明派生类，逐级进行，分步调试。——这种方法适用于做任何的项目）

 

（1）第1个程序： 基类Point类及用于测试的main()函数

#include <iostream.h>class Point{public:Point(double x=0,double y=0); //构造函数double getX( ) const {return x;}              //读x坐标double getY( ) const {return y;}              //读y坐标friend ostream & operator<<(ostream &,const Point &);//重载运算符“<<”protected:double x,y;};//Point的构造函数Point::Point(double a,double b){x=a;y=b;}ostream & operator << (ostream& output,const Point &p){output<<"("<<p.x<<","<<p.y<<")"<<endl;return output;}int main( ){Point p(2,3); cout<<"x="<<p.getX( )<<",y="<<p.getY( )<<endl;                              cout<<"p:"<<p<<endl; return 0;}

 

 

（2）第2个程序：声明Point类的派生类Circle及其测试的main()函数

#include <iostream.h>class Point{public:Point(double x1,double y1){x=x1;y=y1;}//构造函数double getX( )  {return x;}              //读x坐标double getY( )  {return y;}              //读y坐标friend ostream & operator<<(ostream &,const Point &);//重载运算符“<<”protected:double x,y;};ostream & operator << (ostream& output,const Point &p){output<<"("<<p.x<<","<<p.y<<")"<<endl;return output;}class Circle:public Point   //circle是Point类的公用派生类  {  public:      Circle(double x1,double y1,double r1):Point(x1,y1){r=r1; }     double area ( ) ;                   //计算圆面积      friend ostream &operator<<(ostream &, Circle &);//重载运算符“<<”  protected:      double r;  };  double Circle::area( )   {      return 3.14159*r*r;  }  ostream &operator<<(ostream &output, Circle &c)  {      output<<"x="<<c.x<<",y="<<c.y<<",r="<<c.r<<",area="<<c.area( )<<endl;      return output;  }  int main( ){Point p(2,3); cout<<"x="<<p.getX( )<<",y="<<p.getY( )<<endl;                              cout<<"p:"<<p<<endl; Circle c(2,3,4);cout<<"c:"<<c<<endl;return 0;}

 

 

（3）第3个程序：声明Circle的派生类Cylinder及测试的main()函数

#include <iostream.h>class Point{public:Point(double x1,double y1){x=x1;y=y1;}//构造函数double getX( )  {return x;}              //读x坐标double getY( )  {return y;}              //读y坐标friend ostream & operator<<(ostream &,const Point &);//重载运算符“<<”protected:double x,y;};ostream & operator << (ostream& output,const Point &p){output<<"("<<p.x<<","<<p.y<<")"<<endl;return output;}class Circle:public Point   //circle是Point类的公用派生类  {  public:      Circle(double x1,double y1,double r1):Point(x1,y1){r=r1; }     double area ( ) ;                   //计算圆面积      friend ostream &operator<<(ostream &, Circle &);//重载运算符“<<”  protected:      double r;  };  double Circle::area( )   {      return 3.14159*r*r;  }  ostream &operator<<(ostream &output, Circle &c)  {      output<<"x="<<c.x<<",y="<<c.y<<",r="<<c.r<<endl<<"area="<<c.area( )<<endl;      return output;  }  class Cylinder:public Circle  {  public:      Cylinder (double x1,double y1,double r1,double h1):Circle(x1,y1,r1)//构造函数 {height=h1;}      double area( ) ;                         //计算圆表面积      double volume( ) ;                       //计算圆柱体积      friend ostream& operator<<(ostream&, Cylinder&);//重载运算符“<<”  protected:      double height;                               //圆柱高  };  double Cylinder::area( )  {       return 2*Circle::area( )+2*3.14159*r*height;  }  double Cylinder::volume() {      return Circle::area()*height;  }  ostream &operator<<(ostream &output, Cylinder& h)  {      output<<"x="<<h.x<<",y="<<h.y<<",r="<<h.r<<",h="<<h.height<<endl         <<"area="<<h.area( )<<", volume="<<h.volume( )<<endl;      return output;  }   int main( ){Point p(2,3); cout<<"x="<<p.getX( )<<",y="<<p.getY( )<<endl;                              cout<<"p:"<<p<<endl; Circle c(2,3,4);cout<<"c:"<<c<<endl;Cylinder h(2,3,4,5);cout<<"h:"<<h<<endl;return 0;}

 

 

 

总结：只要功夫深，铁棒磨成针、