/* 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 IFTHENELSE_HPP#define IFTHENELSE_HPP// primary template: yield second or third argument depending on first argumenttemplate<bool C, typename Ta, typename Tb>class IfThenElse;// partial specialization: true yields second argumenttemplate<typename Ta, typename Tb>class IfThenElse<true, Ta, Tb> {  public:    typedef Ta ResultT;};// partial specialization: false yields third argumenttemplate<typename Ta, typename Tb>class IfThenElse<false, Ta, Tb> {  public:    typedef Tb ResultT;};#endif // IFTHENELSE_HPP