accum0.hpp

来自「C++_Templates这本书的随书源码」· HPP 代码 · 共 32 行

/* 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 <iterator>

template <typename Iter>
inline
typename std::iterator_traits<Iter>::value_type 
accum (Iter start, Iter end)
{
    typedef typename std::iterator_traits<Iter>::value_type VT;

    VT total = VT();  // assume VT() actually creates a zero value
    while (start != end) {
        total += *start;
        ++start;
    }
    return total;
}

#endif // ACCUM_HPP