accum9.hpp

C++ Templates 完全导引范例

/* The following code example is taken from the book
 * "C++ Templates - The Complete Guide"
 * by David Vandevoorde and Nicolai M. Josuttis, Addison-Wesley, 2002
 *
 * (C) Copyright David Vandevoorde and Nicolai M. Josuttis 2002.
 * Permission to copy, use, modify, sell and distribute this software
 * is granted provided this copyright notice appears in all copies.
 * This software is provided "as is" without express or implied
 * warranty, and with no claim as to its suitability for any purpose.
 */
#ifndef ACCUM_HPP
#define ACCUM_HPP

#include "accumtraits4.hpp"
#include "sumpolicy3.hpp"

template <typename T,
          typename Policy = SumPolicy<>,
          typename Traits = AccumulationTraits<T> >
class Accum {
  public:
    typedef typename Traits::AccT AccT;
    static AccT accum (T const* beg, T const* end) {
        AccT total = Traits::zero();
        while (beg != end) {
            Policy::accumulate(total, *beg);
            ++beg;
        }
        return total;
    }
};

#endif // ACCUM_HPP