How To Find Area Of Circle In C++

This program is about how to find area of circle in c++.

#include<conio.h>
#include<iostream.h>
class  circle
{
float redius;
public :
void input()
{
cout<<"\nRedius : "; cin>>redius;
}
float area()
{
return 3.14*redius*redius;
}
};
class cylinder : public circle
{
float height;
public :
void input()
{
circle::input();
cout<<"\nHeight  : ";
cin>>height;
}
float volume()
{
return area()*height;
}
};
void main()
{
cylinder c;
clrscr();
c.input();
cout<<"\n\n\t Area of Circle ..." << c.area();
cout<<"\n\n\t Volume of Cylinder... " <<c.volume();
getch();
}