cpp/examples/14_rectangle.cpp

#include <iostream>

using namespace std;

class Poly
{
  protected:
	int width;
	int height;

  public:
	Poly(int w, int h) { set_size(w, h); }
	void set_size(int w, int h)
	{
		width = w;
		height = h;
	}
	int get_width() { return width; }
	int get_height() { return height; }
};

class Rectangle : public Poly
{
  public:
	Rectangle(int w, int h) : Poly(w, h) {}
	int area() { return width * height; }
};

int main()
{
	Rectangle x(10, 20);
	cout << "Area of rectangle with sides length " << x.get_width() << " and "
		 << x.get_height() << " is " << x.area() << endl;
	return 0;
}