////   This file contains the C++ code from Program 6.6 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/pgm06_06.cpp//StackAsArray::Iter::Iter (StackAsArray const& _stack) :    stack (_stack)    { Reset (); }bool StackAsArray::Iter::IsDone () const    { return position >= stack.count; }Object& StackAsArray::Iter::operator * () const{    if (position < stack.count)	return *stack.array [position];    else	return NullObject::Instance ();}void StackAsArray::Iter::operator ++ (){    if (position < stack.count)	++position;}void StackAsArray::Iter::Reset ()    { position = 0; }