unit1.h

<<C++Builder 6实用编程100例>>随书光盘

#ifndef SHARP_H
#define SHARP_H
class Sharp
{
public:
        virtual float area() const{return 0.0;}
        virtual void PrintSharpName() const=0;
};
//---------------------------------------------------------------------------
class Point:public Sharp
{
        friend ostream &operator<<(ostream&,const Point&);
public:
        Point(float=0,float=0);
        void setPoint(float,float);
        float getX()const {return x;}
        float getY()const {return y;}
        virtual void PrintSharpName()const {cout<<"Point:";}
private:
        float x,y;      //点的横纵坐标
};
//---------------------------------------------------------------------------
class Circle:public Point
{
        friend ostream &operator<<(ostream&,const Circle&);
public:
        Circle(float=0.00,float=0,float=0);
        void setRadius(float);
        float getRadius()const {return radius;}
        virtual float area()const;
        virtual void PrintSharpName()const {cout<<"Circle:";}
private:
        float radius;   //半径
};
#endif