第十周实验指导--任务3--先建立一个Point(点)类，再派生出一个Circle(圆)类，再派生出一个Cylinder(圆柱体)类

/* (程序头部注释开始)
* 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：定义Complex类中的<<和>>运算符的重载，实现输入和输出，改造原程序中对运算结果显示方式，使程序读起来更自然。

* 作    者：         雷恒鑫                       
* 完成日期：     2012    年 04      月  21    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： 
* 程序输出： 

* 程序头部的注释结束

*/

#include<iostream.h>#include<Cmath>#define pi 3.1415926class Point //定义坐标点类{public:double x,y;   //点的横坐标和纵坐标Point(){x=0;y=0;}Point(double x0,double y0) {x=x0; y=y0;} ~Point (){cout<<"析构函数执行完毕(Destructor function performs finished)"<<endl;}double get_x(){return x;}double get_y(){return y;}friend ostream &operator << (ostream & output, Point & c);  }; 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{private:double d;public:Circle(double xx,double yy,double dd): Point(xx,yy) ,d(dd){}//构造函数~Circle(){}friend ostream &operator << (ostream & output, Circle & c);  double get_d(){return d;}};class Cylinder: public Circle   {private:double h;public:Cylinder(double xx,double yy,double dd,double hh): Circle (xx,yy,dd),h(hh){} //构造函数~Cylinder(){}friend ostream &operator << (ostream & output,Cylinder & c);  double get_h(){return h;}double superficial_area();     //表面积double volume();    //体积};ostream &operator << (ostream & output, Point & c){output<<"点的横坐标为："<<c.x<<"     "<<"点的纵坐标为："<<c.y<<endl;      return output;  }  ostream &operator << (ostream & output, Circle & c){output<<"圆的半径为："<<c.get_d()<<"圆的圆心为"<<"("<<c.get_x()<<","<<c.get_y()<<")"<<endl;      return output;  }ostream &operator << (ostream & output,Cylinder & c){output<<"圆的高为："<<c.get_h()<<"圆的半径为："<<c.get_d()<<"圆的圆心为"<<"("<<c.get_x()<<","<<c.get_y()<<")"<<endl; return output;   }double  Cylinder::superficial_area()     //表面积{double s;s=2*pi*get_d()*get_d()+2*pi*get_d()*get_h();return s;}double  Cylinder::volume()   //体积{double v;v=pi*get_d()*get_d()*get_h();return v;}int main(){Point p(1,1);cout<<p;Circle ci(1,2,6);cout<<ci;Cylinder cy(1,2,3,4);cout<<cy;cout<<"圆柱的体积为："<<cy.volume ()<<endl;cout<<"圆柱的表面积为："<<cy.superficial_area ()<<endl;return 0;}

运行结果：

下面的程序能够看出析构函数的执行过程：

#include<iostream>  using namespace std;#include<Cmath>  #define pi 3.1415926  class Point //定义坐标点类  {  public:      double x,y;   //点的横坐标和纵坐标      Point(){x=0;y=0;}      Point(double x0,double y0) {x=x0; y=y0;}       ~Point ()      {          cout<<"Point析构函数执行完毕(Destructor function performs finished)"<<endl;      }      double get_x(){return x;}      double get_y(){return y;}      friend ostream &operator << (ostream & output, Point & c);    };   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  {  private:      double d;  public:      Circle(double xx,double yy,double dd): Point(xx,yy) ,d(dd){}//构造函数      ~Circle()      {cout<<"Circle析构函数执行完毕(Destructor function performs finished)"<<endl;     }      friend ostream &operator << (ostream & output, Circle & c);        double get_d(){return d;}  };  class Cylinder: public Circle     {  private:      double h;  public:      Cylinder(double xx,double yy,double dd,double hh): Circle (xx,yy,dd),h(hh){} //构造函数      ~Cylinder()      {cout<<"Cylinder析构函数执行完毕(Destructor function performs finished)"<<endl;     }      friend ostream &operator << (ostream & output,Cylinder & c);        double get_h(){return h;}      double superficial_area();     //表面积      double volume();    //体积  };  ostream &operator << (ostream & output, Point & c)  {      output<<"点的横坐标为："<<c.x<<"     "<<"点的纵坐标为："<<c.y<<endl;        return output;    }    ostream &operator << (ostream & output, Circle & c)  {      output<<"圆的半径为："<<c.get_d()<<"圆的圆心为"<<"("<<c.get_x()<<","<<c.get_y()<<")"<<endl;        return output;    }  ostream &operator << (ostream & output,Cylinder & c)  {      output<<"圆的高为："<<c.get_h()<<"圆的半径为："<<c.get_d()<<"圆的圆心为"<<"("<<c.get_x()<<","<<c.get_y()<<")"<<endl;       return output;     }  double  Cylinder::superficial_area()     //表面积  {      double s;      s=2*pi*get_d()*get_d()+2*pi*get_d()*get_h();      return s;  }  double  Cylinder::volume()   //体积  {      double v;      v=pi*get_d()*get_d()*get_h();      return v;  } void f(){ Point p(1,1);      cout<<p;      Circle ci(1,2,6);      cout<<ci;      Cylinder cy(1,2,3,4);      cout<<cy;      cout<<"圆柱的体积为："<<cy.volume ()<<endl;      cout<<"圆柱的表面积为："<<cy.superficial_area ()<<endl;  }int main()  {  f();system("pause");    return 0;  }  

运行结果：