#include <iostream>
using namespace std;
class shape
{
public:double x,y;
void getdata()
{
cout<<"enter x and y\n";
cin>>x>>y;
}
virtual void display_area()=0;
};
class triangle: public shape
{
public:double area;
void display_area()
{
area=(x*y)/12;
cout<<"triangle="<<area;
}
};
class rectangle:public shape
{
public:double area;
void display_area()
{
area=x*y;
cout<<"rectangle="<<area;
}
};
int main()
{
triangle t;
rectangle r;
shape * sptr;
sptr->getdata();
sptr->display_area();
sptr=&r;
sptr->getdata();
sptr->display_area();
return(0);
}