Book Image

Modern C++ Programming Cookbook

By : Marius Bancila
Book Image

Modern C++ Programming Cookbook

By: Marius Bancila

Overview of this book

C++ is one of the most widely used programming languages. Fast, efficient, and flexible, it is used to solve many problems. The latest versions of C++ have seen programmers change the way they code, giving up on the old-fashioned C-style programming and adopting modern C++ instead. Beginning with the modern language features, each recipe addresses a specific problem, with a discussion that explains the solution and offers insight into how it works. You will learn major concepts about the core programming language as well as common tasks faced while building a wide variety of software. You will learn about concepts such as concurrency, performance, meta-programming, lambda expressions, regular expressions, testing, and many more in the form of recipes. These recipes will ensure you can make your applications robust and fast. By the end of the book, you will understand the newer aspects of C++11/14/17 and will be able to overcome tasks that are time-consuming or would break your stride while developing.
Table of Contents (19 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Visiting a std::variant


std::variant is a new standard container added to C++17 based on the boost.variant library. A variant is a type-safe union that holds the value of one of its alternative types. Although in the previous recipe we have seen various operations with variants, the variants we used were rather simple, with POD types mostly, which is not the actual purpose for which std::variant was created. Variants are intended to be used for holding alternatives of similar non-polymorphic and non-POD types. In this recipe, we will see a more real-world example of using variants and will learn how to visit variants.

Getting ready

For this recipe, you should be familiar with the std::variant type. It is recommended that you first read the previous recipe, Using std::variant as a type-safe union.

To explain how variant visitation can be done, we will consider a variant for representing a media DVD. Let's suppose we want to model a store or library that has DVDs that could contain either music...