#include<bits/stdc++.h>
using namespace std;
class Circle;
class Shape
{
public:
    virtual double getArea()=0;
        virtual void Display()=0;

};
class Circle:public Shape
{
    double radius;
public:
    Circle(double r)
    {
        radius=r;
    }
    double getArea()
    {
        return 3.1416*radius*radius;
    }
void Display()
    {
        cout<<getArea()<<endl;
    }
};
class Triangle:public Shape
{
    double height;
    double ground;
public:
    Triangle(double h,double g)
    {
        height=h;
        ground=g;
    }
    double getArea()
    {
        return 0.5*height*ground;
    }
    void Display()
    {
        cout<<getArea()<<endl;
    }
};
int main()
{
    int n;
    double a,h,g;
//    Shape s;
    //Circle o(3);
   // Triangle
    Shape *ptr;
    cout<<"Which area of shape you wanna calculate?"<<endl;
    cout<<"1. "<<"Circle"<<endl;
    cout<<"2. "<<"Triangle"<<endl;
    cin>>n;
    if(n==1)
    {
        cout<<"Enter radius of Circle:";
        cin>>a;
    Circle o(a);
    ptr = &o;
    ptr->getArea();
    cout<<"Area is:";
    ptr->Display();
    }
    else if(n==2)
    {
        cout<<"Enter height and ground:";
        cin>>h;
        cin>>g;
        Triangle t(h,g);
        ptr = &t;
        ptr->getArea();
        ptr->Display();
    }
}