examples/manual/permutation.cpp

/**************************************************************************
 *
 * permute.cpp - Example program of permutations.
 *
 * $Id$
 *
 ***************************************************************************
 *
 * Copyright (c) 1994-2005 Quovadx,  Inc., acting through its  Rogue Wave
 * Software division. Licensed under the Apache License, Version 2.0 (the
 * "License");  you may  not use this file except  in compliance with the
 * License.    You    may   obtain   a   copy   of    the   License    at
 * http://www.apache.org/licenses/LICENSE-2.0.    Unless   required    by
 * applicable law  or agreed to  in writing,  software  distributed under
 * the License is distributed on an "AS IS" BASIS,  WITHOUT WARRANTIES OR
 * CONDITIONS OF  ANY KIND, either  express or implied.  See  the License
 * for the specific language governing permissions  and limitations under
 * the License.
 * 
 **************************************************************************/

#include <algorithm>  // for next_permutation, prev_permutation
#include <functional> // for less
#include <iostream>   // for cout, endl
#include <iterator>   // for ostream_iterator
#include <numeric>    // for accumulate
#include <vector>     // for vector

#include <examples.h>

int main ()
{
    typedef std::vector<int, std::allocator<int> > IntVec;
    typedef std::vector<char, std::allocator<char> > CharVec;

    // Initialize a vector using an array of integers.
    const IntVec::value_type  a1[] = { 0, 0, 0, 0, 1, 0, 0, 0, 0, 0 };
    const CharVec::value_type a2[] = "abcdefghji";

    // Create the initial set and copies for permuting.
    IntVec m1      (a1 + 0, a1 + sizeof a1 / sizeof *a1); 
    IntVec prev_m1 (10);
    IntVec next_m1 (10);

    CharVec m2      (a2 + 0, a2 + sizeof a2 / sizeof *a2 - 1);
    CharVec prev_m2 (10);
    CharVec next_m2 (10);

    std::copy (m1.begin (), m1.end (), prev_m1.begin ());
    std::copy (m1.begin (), m1.end (), next_m1.begin ());
    std::copy (m2.begin (), m2.end (), prev_m2.begin ());
    std::copy (m2.begin (), m2.end (), next_m2.begin ());

    // Create permutations.
    typedef std::less<IntVec::value_type>  IntLess;
    typedef std::less<CharVec::value_type> CharLess;

    std::prev_permutation (prev_m1.begin (), prev_m1.end (), IntLess ());
    std::next_permutation (next_m1.begin (), next_m1.end (), IntLess ());
    std::prev_permutation (prev_m2.begin (), prev_m2.end (), CharLess ());
    std::next_permutation (next_m2.begin (), next_m2.end (), CharLess ());

    // Output results.

    typedef std::ostream_iterator<IntVec::value_type, char,
                                  std::char_traits<char> >
        IntOSIter;

    typedef std::ostream_iterator<CharVec::value_type, char,
                                  std::char_traits<char> >
        CharOSIter;

    std::cout << "Example 1: \n     Original values:      ";
    std::copy (m1.begin (), m1.end (), IntOSIter (std::cout, " "));

    std::cout << "\n     Previous permutation: ";
    std::copy (prev_m1.begin (), prev_m1.end (), IntOSIter (std::cout, " "));

    std::cout << "\n     Next Permutation:     ";
    std::copy (next_m1.begin (), next_m1.end (), IntOSIter (std::cout, " "));

    std::cout << "\n\nExample 2: \n     Original values:      ";
    std::copy (m2.begin (), m2.end (), CharOSIter (std::cout, " "));     

    std::cout << "\n     Previous Permutation: ";
    std::copy (prev_m2.begin (), prev_m2.end (), CharOSIter (std::cout, " "));

    std::cout << "\n     Next Permutation:     ";
    std::copy (next_m2.begin (), next_m2.end (), CharOSIter (std::cout, " "));  

    std::cout << std::endl << std::endl;

    return 0;
}