/* 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. */#include "forwardparam.hpp"template <typename C, int N> class BaseMem : public C {  public:    BaseMem(C& c) : C(c) { }    BaseMem(C const& c) : C(c) { }};template <typename FO1, typename FO2>class Composer : private BaseMem<FO1,1>,                 private BaseMem<FO2,2> {  public:    // to let it fit in our framework:    enum { NumParams = FO1::NumParams };    typedef typename FO2::ReturnT ReturnT;    typedef typename FO1::Param1T Param1T;    // constructor: initialize function objects    Composer(FO1 f1, FO2 f2)     : BaseMem<FO1,1>(f1), BaseMem<FO2,2>(f2) {    }    // ``function call'': nested call of function objects    ReturnT operator() (typename ForwardParamT<Param1T>::Type v) {        return BaseMem<FO2,2>::operator()                 (BaseMem<FO1,1>::operator()(v));    }};