/* 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 SUMPOLICY_HPP#define SUMPOLICY_HPPtemplate<bool use_compound_op = true>class SumPolicy {  public:    template<typename T1, typename T2>    static void accumulate (T1& total, T2 const & value) {        total += value;    }};template<>class SumPolicy<false> {  public:    template<typename T1, typename T2>    static void accumulate (T1& total, T2 const & value) {        total = total + value;    }};#endif // SUMPOLICY_HPP