Book Image

Template Metaprogramming with C++

By : Marius Bancila
5 (1)
Book Image

Template Metaprogramming with C++

5 (1)
By: Marius Bancila

Overview of this book

Learn how the metaprogramming technique enables you to create data structures and functions that allow computation to happen at compile time. With this book, you'll realize how templates help you avoid writing duplicate code and are key to creating generic libraries, such as the standard library or Boost, that can be used in a multitude of programs. The introductory chapters of this book will give you insights into the fundamentals of templates and metaprogramming. You'll then move on to practice writing complex templates and exploring advanced concepts such as template recursion, template argument deduction, forwarding references, type traits, and conditional compilation. Along the way, you'll learn how to write variadic templates and how to provide requirements to the template arguments with C++20 constraints and concepts. Finally, you'll apply your knowledge of C++ metaprogramming templates to implement various metaprogramming patterns and techniques. By the end of this book, you'll have learned how to write effective templates and implement metaprogramming in your everyday programming journey.
Table of Contents (16 chapters)
Part 1: Core Template Concepts
Part 2: Advanced Template Features
Part 3: Applied Templates
Appendix: Closing Notes

Chapter 3, Variadic Templates

Question 1

What are variadic templates and why are they useful?


Variadic templates are templates with a variable number of arguments. They allow us to write not only functions with variable number of arguments but also class templates, variable templates, and alias templates. Unlike other approaches, such as the use of the va_ macros, they are type-safe, do not require macros, and do not require us to explicitly specify the number of arguments.

Question 2

What is a parameter pack?


There are two kinds of parameter packs: template parameter packs and function parameter packs. The former are template parameters that accept zero, one, or more template arguments. The latter are function parameters that accept zero, one, or more function arguments.

Question 3

What are the contexts where parameter packs can be expanded?


Parameter packs can be expanded in a multitude of contexts, as follows: template parameter...