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

Defining member function templates

So far, we have learned about function templates and class templates. It is possible to define member function templates too, both in non-template classes and class templates. In this section, we will learn how to do this. To understand the differences, let's start with the following example:

template <typename T>
class composition
   T add(T const a, T const b)
      return a + b;

The composition class is a class template. It has a single member function called add that uses the type parameter T. This class can be used as follows:

composition<int> c;
c.add(41, 21);

We first need to instantiate an object of the composition class. Notice that we must explicitly specify the argument for the type parameter T because the compiler is not able to figure it out by itself (there is no context from which to infer it). When we invoke...