partial_sum.cpp

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#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;
}