examples/manual/partial_sum.cpp

/**************************************************************************
 *
 * partsum.cpp - Example program for partial sum.
 *
 * $Id$
 *
 ***************************************************************************
 *
 * 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 copy
#include <functional> // for multiplies
#include <iostream>   // for cout, endl
#include <iterator>   // for ostream_iterator
#include <numeric>    // for partial_sum
#include <vector>     // for vector

#include <examples.h>


int main ()
{
    typedef std::vector<int, std::allocator<int> >                    Vector;
    typedef std::ostream_iterator<int, char, std::char_traits<char> > Iter;

    // Initialize a vector using an array of integers.
    const Vector::value_type a[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
    Vector v (a + 0, a + sizeof a / sizeof *a);

    // Create an empty vectors to store results.
    Vector sums  (Vector::size_type (10));
    Vector prods (Vector::size_type (10));

    // Compute partial_sums and partial_products.
    std::partial_sum (v.begin (), v.end (), sums.begin ());
    std::partial_sum (v.begin (), v.end (), prods.begin (),
                      std::multiplies<Vector::value_type>());

    // Output the results.
    std::cout << "For the series: \n     ";
    std::copy (v.begin (), v.end (), Iter (std::cout, " "));

    std::cout << "\n\nThe partial sums: \n     ";
    std::copy (sums.begin (), sums.end (), Iter (std::cout, " "));
    std::cout << " should each equal (N*N + N)/2\n\n";

    std::cout << "The partial products: \n     ";
    std::copy (prods.begin (), prods.end (), Iter (std::cout, " "));
    std::cout << " should each equal N!" << std::endl;

    return 0;
}