Book Image

Modern C++ Programming Cookbook - Second Edition

By : Marius Bancila
5 (1)
Book Image

Modern C++ Programming Cookbook - Second Edition

5 (1)
By: Marius Bancila

Overview of this book

C++ has come a long way to be one of the most widely used general-purpose languages that is fast, efficient, and high-performance at its core. The updated second edition of Modern C++ Programming Cookbook addresses the latest features of C++20, such as modules, concepts, coroutines, and the many additions to the standard library, including ranges and text formatting. The book is organized in the form of practical recipes covering a wide range of problems faced by modern developers. The book also delves into the details of all the core concepts in modern C++ programming, such as functions and classes, iterators and algorithms, streams and the file system, threading and concurrency, smart pointers and move semantics, and many others. It goes into the performance aspects of programming in depth, teaching developers how to write fast and lean code with the help of best practices. Furthermore, the book explores useful patterns and delves into the implementation of many idioms, including pimpl, named parameter, and attorney-client, teaching techniques such as avoiding repetition with the factory pattern. There is also a chapter dedicated to unit testing, where you are introduced to three of the most widely used libraries for C++: Boost.Test, Google Test, and Catch2. By the end of the book, you will be able to effectively leverage the features and techniques of C++11/14/17/20 programming to enhance the performance, scalability, and efficiency of your applications.
Table of Contents (16 chapters)
13
Bibliography
14
Other Books You May Enjoy
15
Index

Using std::variant as a type-safe union

In C++, union is a special class type that, at any point, holds a value of one of its data members. Unlike regular classes, unions cannot have base classes, nor can they be derived, and they cannot contain virtual functions (that would not make sense anyway). Unions are mostly used to define different representations of the same data. However, unions only work for types that are Plain Old Data (POD). If a union contains values of non-POD types, then these members require explicit construction with a placement new and explicit destruction, which is cumbersome and error-prone. In C++17, a type-safe union is available in the form of a standard library class template called std::variant. In this recipe, you will learn how to use it to model alternative values.

Getting ready

Although discriminated unions are not directly discussed in this recipe, being familiar with them will help us understand the design of, and the way, variant...