/* Code for exercise 18.1. |  | "C++ Solutions--Companion to The C++ Programming Language, Third Edition" | by David Vandevoorde; Addison-Wesley 1998; ISBN 0-201-30965-3. | | Permission to use, copy, modify, distribute and sell this software | and its documentation for any purpose is hereby granted without fee. | The author makes no representations about the suitability of this | software for any purpose.  It is provided "as is" without express or | implied warranty. `----------------------------------------------------------------------*/#include <algorithm>#include <iostream>#include <vector>template<typename R, typename T, typename P1>struct mem_fun1_ref_t {   typedef R return_type;   typedef T first_argument_type;   typedef P1 second_argument_type;   typedef R (T::*PMF)(P1); // PMF is a pointer-to-member-                            // function type (