////   This file contains the C++ code from Program 7.2 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/pgm07_02.cpp//class ListAsArray : public virtual OrderedList{protected:    Array<Object*> array;    class Pos;public:    ListAsArray (unsigned int);    // ...    friend class Pos;};