c++之继承二

下面的实例是使用继承完成点、圆、圆柱体的层次结构

  1 #include <iostream>
  2 using namespace std;
  3 #define PI 3.1415926
  4
  5 class Point
  6 {
  7     friend ostream& operator << (ostream& output,Point&);
  8 public:
  9     Point(int x =0,int y =0);    //带默认参数的构造函数
 10     void setPoint(int x,int y);    //设置点坐标
 11     int getX();    //得到点的x轴坐标
 12     int getY();    //得到点的y轴坐标
 13 protected:    //成员函数，x，y轴的坐标
 14     int x,y;
 15 };
 16
 17 class Circle: public Point        //类Circle公有继承Point
 18 {
 19     friend ostream& operator << (ostream& output,Circle&);
 20 public:
 21     Circle(double r = 0.0,int x =0,int y =0);    //带默认参数的构造函数
 22     void setRadius(double r);    //设置圆的半径
 23     double getRadius();        //得到圆的半径
 24     double getArea();        //得到圆的面积
 25 protected:
 26     double radius;        //成员函数，半径
 27 };
 28
 29 class Cylinder:public Circle    //类Cylinder继承Circle
 30 {
 31     friend ostream& operator <<(ostream& output,Cylinder&);
 32 public:
 33     Cylinder(double height=0.0,double radius =0.0,int x=0,int y=0);        //带默认参数的构造函数
 34     void setHeight(double height);    //设置圆柱体高度值
 35     double getHeight();    //返回圆柱体的高度值
 36     double getArea();    //返回圆柱体的面积
 37     double getVolume();    //返回圆柱体的体积
 38 protected:
 39     double height;    //成员函数，圆柱体的高度
 40 };
 41
 42 //Point类的实现
 43 Point::Point(int x,int y)
 44 {
 45     this->x = x;
 46     this->y = y;
 47 }
 48 void Point::setPoint(int x,int y)
 49 {
 50     this->x = x;
 51     this->y = y;
 52 }
 53 int Point::getX()
 54 {
 55     return this->x;
 56 }
 57 int Point::getY()
 58 {
 59     return this->y;
 60 }
 61 ostream& operator <<(ostream& output,Point& point)
 62 {
 63     cout << "[point: x="<<point.getX()<<" ,"<<"y="<<point.getY() << "]" <<endl;
 64     return output;
 65 }
 66
 67 //Circle类的实现
 68 Circle::Circle(double radius,int x,int y):Point(x,y)
 69 {
 70     this->radius = radius;
 71 }
 72 void Circle::setRadius(double radius)
 73 {
 74     this->radius = radius;
 75 }
 76 double Circle::getRadius()
 77 {
 78     return this->radius;
 79 }
 80 double Circle::getArea()
 81 {
 82     return PI * radius * radius;
 83 }
 84 ostream& operator <<(ostream& output,Circle& circle)
 85 {
 86     cout << "[circle: x=" << circle.getX() << " ,y=" <<circle.getY() <<" ,radius=" << circle.getRadius() << " ,area=" <<circle.getArea() << "]"<<endl;
 87     return output;
 88 }
 89
 90 //类Cylinder的实现
 91 Cylinder::Cylinder(double height,double radius,int x,int y):Circle(radius,x,y)
 92 {
 93     this->height = height;
 94 }
 95
 96 void Cylinder::setHeight(double height)
 97 {
 98     this->height = height;
 99 }
100 double Cylinder::getHeight()
101 {
102     return this->height;
103 }
104 double Cylinder::getArea()
105 {
106     return 2*Circle::getArea()+2 * PI * radius * height;
107 }
108 double Cylinder::getVolume()
109 {
110     return Circle::getArea()*height;
111 }
112 ostream& operator <<(ostream& output,Cylinder& cylinder)
113 {
114     cout << "[cylinder: x=" << cylinder.getX() << " ,y=" <<cylinder.getY() << " ,height=" << cylinder.getHeight() <<" ,radius=" << cylinder.getRadius() << " ,area=" <<cylinder.getArea() <<" ,volume=" << cylinder.getVolume()<< "]"<<endl;
115     return output;
116 }
117
118 void main()
119 {
120     Point p ( 72, 115 ) ;        //定义点对象并初始化
121    cout << "The initial location of p is " << p << endl ;
122    p.setPoint ( 10, 10 ) ;        //置点的新数据值
123    cout << "\nThe new location of p is " << p << endl ;    //输出数据
124    Circle c ( 2.5, 37, 43 ) ;    //定义圆对象并初始化
125    cout<<"\nThe initial location and radius of c are\n"<<c<<"\nArea = "<<c.getArea()<<"\n" ;
126    //置圆的新数据值
127    c.setRadius ( 4.25 ) ;
128    c.setPoint ( 2, 2 ) ;
129    //输出圆心坐标和圆面积
130    cout<<"\nThe new location and radius of c are\n"<<c<<"\nArea = "<<c.getArea()<< "\n" ;
131    Cylinder cyl ( 5.7, 2.5, 12, 23 ) ;    //定义圆柱体对象并初始化
132    //输出圆柱体各数据和表面积，体积
133    cout << "\nThe initial location, radius ang height of cyl are\n" << cyl
134        << "Area = " << cyl.getArea() << "\nVolume = " << cyl.getVolume() << ‘\n‘;
135    //置圆柱体的新数据值
136    cyl.setHeight ( 10 ) ;
137    cyl.setRadius ( 4.25 ) ;
138    cyl.setPoint ( 2, 2 ) ;
139    cout << "\nThe new location, radius ang height of cyl are\n" << cyl
140        << "Area = " << cyl.getArea() << "\nVolume = "<<cyl.getVolume()<< "\n" ;
141 }