STL/algorithm/for each

 
#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
 
class CSum : std::unary_function<int, void> 
{
public:
    argument_type m_sum;
    CSum() { m_sum = 0; }
    result_type operator()(argument_type i) 
    {
        m_sum += i;
    }
};
int main()
{
    std::vector<int> coll;
    for( int n = 1; n < 16; ++n) coll.push_back( n);
    std::copy( coll.begin(), coll.end(), std::ostream_iterator<int>(std::cout, " ") );
 
    CSum s;
    s = std::for_each( coll.begin(), coll.end(), CSum());
    std::cout << "sum of v: " << s.m_sum << std::endl;
    return 0;
}