C++ 类族的设计

  1 /*
  2 *Copyright (c)2014,烟台大学计算机与控制工程学院
  3 *All rights reserved.
  4 *文件名称：d.cpp
  5 *作    者：张旺华
  6 *完成日期：2015年6月1日
  7 *版 本 号：v1.0
  8 */
  9 #include <iostream>
 10 
 11 using namespace std;
 12 const double pi=3.1415926;
 13 class Point
 14 {
 15 public:
 16     Point (double X=0,double Y=0):x(X),y(Y){}
 17     ~Point();
 18     void setPoint(double,double);
 19     double getx()const {return x;};
 20     double gety()const {return y;};
 21     friend ostream &operator<<(ostream &output,Point & p);
 22 protected:
 23     double x,y;
 24 };
 25 Point::~Point()
 26 {}
 27 void Point::setPoint(double a,double b)
 28 {
 29     x=a;
 30     y=b;
 31 }
 32 ostream &operator<<(ostream &output,Point & p)
 33 {
 34     output<<"["<<p.x<<","<<p.y<<"]";
 35     return output;
 36 }
 37 class Circle: public Point
 38 {
 39 public :
 40     Circle(double a=0,double b=0,double r=0);
 41     ~Circle();
 42     void setCircle(double a,double b,double r);
 43     void setRadius(double r) { R=r;}
 44     double getRadius(){return R;}
 45     double area()const {return pi*R*R;}
 46     double girth()const {return pi*R*2;}
 47      friend ostream &operator<<(ostream &output,Circle & c);
 48 protected:
 49     double R;
 50 };
 51  Circle::~Circle(){}
 52 void Circle::setCircle(double a,double b,double r)
 53 {
 54     Point(a,b);
 55     R=r;
 56 }
 57 Circle::Circle(double a,double b,double r):Point(a,b),R(r){}
 58 
 59 ostream &operator<<(ostream &output,Circle & c)
 60 {
 61     output<<"R="<<c.R<<"   Center=["<<c.x<<", "<<c.y<<"], r="<<c.R<<"  area="<<c.area()<<"  girth="<<c.girth();
 62 }
 63 class Cylinder:public Circle
 64 {
 65 public:
 66     Cylinder (double x=0,double y=0,double r=0,double h=0);//构造函数
 67     void setHeight(double);                      //设置圆柱高
 68     double getHeight( ) const;                    //读取圆柱高
 69     double area( ) const;                         //计算圆柱表面积
 70     double volume( ) const;                       //计算圆柱体积
 71     friend ostream& operator<<(ostream&,const Cylinder&);//重载运算符“<<”
 72 protected:
 73     double height;                               //圆柱高
 74 };
 75 
 76 //定义构造函数
 77 Cylinder::Cylinder(double a,double b,double r,double h) :Circle(a,b,r),height(h){}
 78 
 79 //设置圆柱高
 80 void Cylinder::setHeight(double h)
 81 {
 82     height=h;
 83 }
 84 
 85 //读取圆柱高
 86 double Cylinder::getHeight( ) const
 87 {
 88     return height;
 89 }
 90 
 91 //计算圆柱表面积
 92 double Cylinder::area( ) const
 93 {
 94     return 2*Circle::area( )+2*Circle::girth()*height;
 95 }
 96 
 97 //计算圆柱体积
 98 double Cylinder::volume() const
 99 {
100     return Circle::area()*height;
101 }
102 
103 //重载运算符“<<”
104 ostream &operator<<(ostream &output,const Cylinder& cy)
105 {
106     output<<"Center=["<<cy.x<<","<<cy.y<<"], r="<<cy.R<<", h="<<cy.height
107         <<"\narea="<<cy.area( )<<", volume="<<cy.volume( )<<endl;
108     return output;
109 }
110 
111 int main( )
112 {
113     Cylinder cy1(3.5,6.4,5.2,10);
114     cout<<"\noriginal cylinder:\nx="<<cy1.getx( )<<", y="<<cy1.gety( )<<", r="
115         <<cy1.getRadius( )<<", h="<<cy1.getHeight( )<<"\narea="<<cy1.area()
116         <<",volume="<<cy1.volume()<<endl;
117     cy1.setHeight(15);
118     cy1.setRadius(7.5);
119     cy1.setPoint(5,5);
120     cout<<"\nnew cylinder:\n"<<cy1;
121     return 0;
122 }