ABSTRACT     Class and function templates add another dimension of programming power to the C++ language. Computation of constants, evaluation of expressions, polymorphic dispatch of functions are examples of tasks that can be solved at compile time rather than at run time - using templates. In this lecture, we explore advanced template programming techniques that can replace corresponding object oriented idioms and help eliminated the run time overhead of traditional object oriented programming.  Polymorphism is one of the classic ideas of object oriented programming. In C++, it typically involves inheritance and virtual function dispatch at run time. Using templates, polymorphic behavior can be dispatched at compile time already, thus eliminating any run time overhead. The strategy pattern deals with interchangeable algorithms and suggests an implementation technique that involves inheritance. The use of templates provides a run-time efficient alternative technique, sometimes referred to as policy mix-ins. The C++ template instantiator is a primitive recursive function evaluator. Certain expressions and constants can be computed recursively at compile time rather than at run time. In this lecture, we explore function templates, function pointers, function object types, traits, the typename keyword, explicit function template argument specification, function template overloading, and other advanced template features.

Level:	intermediate
Duration:	2 hours
Prerequisites:	Attendants should be familiar with the concept and pre-standard language constructs for template programming in C++. Any knowledge of recently added template features is not required.
Presented at:	C++ World , New York, NY, August 1998  Application Development '99 , London, UK, July 1999