#include <iostream>
using namespace std;

class Shape {
protected:
  int width, height;

public:
  Shape( int a = 0, int b = 0){
    width = a;
    height = b;
  }
  int area() {
    cout << "Parent class area :" <<endl;
    return 0;
  }
};
class Rectangle: public Shape {
public:
  Rectangle( int a = 0, int b = 0):Shape(a, b) { }

  int area () {
    cout << "Rectangle class area :" <<endl;
    return (width * height);
  }
};

class Triangle: public Shape {
public:
  Triangle( int a = 0, int b = 0):Shape(a, b) { }

  int area () {
    cout << "Triangle class area :" <<endl;
    return (width * height / 2);
  }
};

// Main function for the program
int main() {
  Shape *shape;
  Rectangle rec(10,7);
  Triangle  tri(10,5);

  // store the address of Rectangle
  shape = &rec;

  // call rectangle area.
  shape->area();

  // store the address of Triangle
  shape = &tri;

  // call triangle area.
  shape->area();

  return 0;
}