大足海棠小学招生电话:请教C＋＋高手

#include<iostream.h>
class Shape
{public:
Shape(double=0.0,double=0.0);
virtual void setpoint()=0;
protected:
double x,y;
};
Shape::Shape(double a,double b)
{x=a;
y=b;}

class TwoDimShape:public Shape
{public:
TwoDimShape(double=0.0,double=0.0);
void setpoint()
{cout<<"the point of the center is : "<<'('<<x<<","<<y<<')'<<endl;}
virtual void setSide()=0;
};
TwoDimShape::TwoDimShape(double a,double b):Shape(a,b){}

class Circle:public TwoDimShape
{public:
Circle(double=0,double=0.0,double=0.0);
void setSide(double);
void putSide(){cout<<"the Radius of the circle is :"<<Radius<<endl;}
protected:
double Radius;
};
Circle::Circle(double r,double a,double b):TwoDimShape(a,b)
{setSide(r);}
void Circle::setSide(double r)
{Radius=r;
}
void main()
{Circle c(1.5,2.1,1.1);
c.setpoint();
c.putSide();}
这程序错在哪，能帮我解决的我加五十分
我说的话当然算数，不过你的回答不太正确，它的要求是TwoDimShape类为抽象类，然后再派生出Circle．刚才已经有人给我解答了，不过还是谢谢你