////   This file contains the C++ code from Program 12.12 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/pgm12_12.cpp//MultisetAsArray operator + (    MultisetAsArray const& s, MultisetAsArray const& t){    if (s.universeSize != t.universeSize)	throw invalid_argument ("mismatched sets");    MultisetAsArray result (s.universeSize);    for (unsigned int i = 0; i < s.universeSize; ++i)	result.array [i] = s.array [i] + t.array [i];    return result;}MultisetAsArray operator * (    MultisetAsArray const& s, MultisetAsArray const& t){    if (s.universeSize != t.universeSize)	throw invalid_argument ("mismatched sets");    MultisetAsArray result (s.universeSize);    for (unsigned int i = 0; i < s.universeSize; ++i)	result.array [i] = Min (s.array [i], t.array [i]);    return result;}MultisetAsArray operator - (    MultisetAsArray const& s, MultisetAsArray const& t){    if (s.universeSize != t.universeSize)	throw invalid_argument ("mismatched sets");    MultisetAsArray result (s.universeSize);    for (unsigned int i = 0; i < s.universeSize; ++i)	if (t.array [i] <= s.array [i])	    result.array [i] = s.array [i] - t.array [i];    return result;}