////   This file contains the C++ code from Program A.10 of//   "Data Structures and Algorithms//    with Object-Oriented Design Patterns in C++"//   by Bruno R. Preiss.////   Copyright (c) 1998 by Bruno R. Preiss, P.Eng.  All rights reserved.////   http://www.pads.uwaterloo.ca/Bruno.Preiss/books/opus4/programs/pgm0A_10.cpp//class Circle : public GraphicalObject{    int radius;public:    Circle (Point const& p, int r) :	GraphicalObject (p), radius (r) {}    void Draw () const;};class Rectangle : public GraphicalObject{    int height;    int width;public:    Rectangle (Point const& p, int ht, int wid) :	GraphicalObject (p), height (ht), width (wid) {}    void Draw () const;};class Square : public Rectangle{public:    Square (Point const& p, int wid) :	Rectangle (p, wid, wid) {}};