// We have added a new member function (perimeter) to the 
// subclass Rectangle. Subclasses can have many more data members
// and member functions besides the ones they inherit from their
// base class.

#include <iostream>
using namespace std;

class Shape {
  protected:
    int width, height;
  public:
    Shape() { width = height = 0; }
    Shape(int w, int h) { width = w; height = h; }
    void display() const;
};

void Shape::display() const {
  cout << width << " " << height << endl; 
}

class Rectangle : public Shape {
  public:
    Rectangle() {}
    Rectangle(int w, int h) : Shape(w, h) { }
    int perimeter() const;
};

int Rectangle::perimeter() const{
  return 2 * width + 2 * height;
}

int main() {
  Rectangle r;
  Rectangle q(4,5);
  r.display();
  q.display();
  cout << "Perimeter of q is: " << q.perimeter() << endl;
  return 0;
}