Write a C++ program to calculate area of circle,sphere and cylinder using base class round-shape

Create a base class round-shape(radius). define three different
shapes as circle, sphere and cylinder(height) from round-shape.
class round-shape
{
protected :float radius;
public:static float pi;
round-shape(float)//default argument
virtual float area()=0;
}
Write a C++ program to calculate area of circle,sphere and cylinder



#include<iostream.h>
#include<conio.h>
class round
{
protected:float radius;
public:static float pi;
       round(float r=0)
       {
       cout<<"\n Enter the radius:-";
       cin>>r;
       radius=r;
       }
       virtual float area()=0;
       };
class circle:public round
{
public:float circle;
       float area()
       {
       circle=pi*radius*radius;
       cout<<"\n Area of circle:-"<<circle;
       return 0;
       }
       };
class sphere:public round
{
public:float sph;
       float area()
       {
       sph=4*pi*radius*radius;
       cout<<"\n Area of sphere:-"<<sph;
       return 0;
       }
};
class cylinder:public round
{
public:float ac;
       float h;
public:cylinder(float height=0)
       {
       cout<<"\n Enter height:-";
       cin>>height;
       h=height;
       }
       float area()
       {
       float tsac,csac,vc,acbc;
       tsac=2*pi*radius*(h+radius);
       csac=2*pi*radius*h;
       vc=pi*radius*radius*h;
       acbc=pi*radius*radius;
       ac=tsac+csac+vc+acbc;
       cout<<"Area of cylinder is:-"<<ac;
       return 0;
       }
};
float round::pi=3.14;
int main()
{
int height;
clrscr();
cout<<"\n\t\t To calculate area of circle\n\n";
circle c;
c.area();
cout<<"\n\t\t To calculate area of sphere\n\n";
sphere s;
s.area();
cout<<"\n\t\t To calculate area of cylinder\n\n";
cylinder cl;
cl.area();
getch();
return 0;
}






============================================
OUTPUT

                To calculate area of circle                                    
                                                                               
                                                                               
Enter the radius:-1                                                           
                                                                               
Area of circle:-3.14         
                                                 
                To calculate area of sphere                                    
                                                                               
                                                                               
Enter the radius:-1                                                           
                                                                               
Area of sphere:-12.56  
                                                       
                To calculate area of cylinder                                  
                                                                               
                                                                               
Enter the radius:-1                                                           
                                                                               
Enter height:-1
Area of cylinder is:-25.120001