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)
1
Part 1: Core Template Concepts
5
Part 2: Advanced Template Features
9
Part 3: Applied Templates
Appendix: Closing Notes

Understanding and defining type traits

In a nutshell, type traits are small class templates that contain a constant value whose value represents the answer to a question we ask about a type. An example of such a question is: is this type a floating-point type? The technique for building type traits that provide such information about types relies on template specialization: we define a primary template as well as one or more specializations.

Let’s see how we can build a type trait that tells us, at compile-time, whether a type is a floating-point type:

template <typename T>
struct is_floating_point
{
   static const bool value = false;
};
template <>
struct is_floating_point<float>
{
   static const bool value = true;
};
template <>
struct is_floating_point<double>
{
   static const bool value = true;
};
template <>
struct is_floating_point<long double>
{
   static const...