////   This file contains the C++ code from Program 7.9 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_09.cpp//void ListAsArray::Withdraw (Position const& arg){    Pos const& position = dynamic_cast<Pos const&> (arg);    if (count == 0)	throw domain_error ("list is empty");    if (&position.list != this || position.offset >= count)	throw invalid_argument ("invalid position");    for (unsigned int i = position.offset; i < count-1U; ++i)	array [i] = array [i + 1];    --count;}