/* 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 <iostream>#include <string>#include <typeinfo>#include "funcptr.hpp"double seven() {    return 7.0;}std::string more() {    return std::string("more");}template <typename FunctorT>void demo (FunctorT func) {    std::cout << "Functor returns type "              << typeid(typename FunctorT::ReturnT).name() << '\n'              << "Functor returns value "              << func() << '\n';}int main() {    demo(func_ptr(seven));    demo(func_ptr(more));}