#include <iostream.h>
const double PI = 3.14;
class Shape
{ public:
      virtual double area()=0;
      virtual double surface_area()=0;     
      virtual double volume()=0;
};
class Circle:virtual public Shape
{ 
protected:
            double r;
public:
          Circle(double x)
             { r=x;}
          double area()
             { return PI*r*r; }
};
class Ball:virtual public Circle
{
public:
          Ball(double x):Circle(x){}
          double surface_area()
             { return 4*PI*r*r; }
          double volume()
             { return (4/3)*PI*r*r*r;}
};
class Taper:virtual public Circle
{
protected:
          double l;
public:
          Taper(double x,double y):Circle(x)
          {l=y;}
          double surface_area()
             { return PI*r*l+PI*r*r; }
          double volume()
             { return (1/3)*PI*r*r*l;}
};
class Cylinder:virtual public Circle
{
protected:
          double h;
public:
          Taper(double x,double y):Circle(x)
          {h=y;}
          double surface_area()
             { return 2*PI*r*h+2*PI*r*r; }
          double volume()
             { return PI*r*r*h;}
};
int main ( )
{    Circle c(1.1);
     Ball b(2.2);
     Taper t(3.3,4.4);
     Cylinder m(5.5,6.6);
     Shape *p;
     p=&c;
     cout<<"the area of Circle is:"<<p->area()<<endl;
     p=&b;
     cout<<"the surface_area of Ball:"<<p->surface_area()<<endl;
     cout<<"the Volume of Ball:"<<p->Volume()<<endl;
     p=&t;
     cout<<"the surface_area of Taper is:"<<p->surface_area()<<endl;
     cout<<"the Volume of Taper:"<<p->Volume()<<endl;
     p=&m;
     cout<<"the surface_area of Cylinder is:"<<p->surface_area()<<endl;
     cout<<"the Volume of Cylinder:"<<p->Volume()<<endl;
}
这个也是求解虚函数和纯虚函数下的面积和体积，为什么调不出来，谁能修改一下给出正确的程序！谢谢！