#include<iostream>			//pgm on class polygon
using namespace std;
class polygon
{
	protected:
		float width, height;
	public:
		void input()
		{
			cout<<"\nEnter the height and width: ";
			cin>>height>>width;
		}
		virtual float area()=0;
};
class rectangle: public polygon
{
	public:

		float area()
		{
			input();
			return width*height;
		}
};
class triangle:public polygon
{
	public:
		//input();
		float area()
		{
			input();
			return (width*height)*0.5;
		}
};
int main()
{
	polygon *p;
	char ch;
	float a;
	int opt;
	do
	{
		cout<<"\nEnter \n1 - area of rectangle\n2 - area of triangle\n";
		cin>>opt;
		switch(opt)
		{
			case 1:
				p=new rectangle;

				a=p->area();
				cout<<"\nArea of rectangle is : "<<a;
				break;
			case 2:
				p=new triangle;

				a=p->area();
				cout<<"\nArea of triangle is : "<<a;
				break;
			default:
				cout<<"\nInvalid option";
		}
		cout<<"\nDo you want to continue? [y/n] : ";
		cin>>ch;
	}while(ch=='y'|ch=='Y');
	delete p;
}