Book Image

C++17 STL Cookbook

By : Jacek Galowicz
Book Image

C++17 STL Cookbook

By: Jacek Galowicz

Overview of this book

C++ has come a long way and is in use in every area of the industry. Fast, efficient, and flexible, it is used to solve many problems. The upcoming version of C++ will see programmers change the way they code. If you want to grasp the practical usefulness of the C++17 STL in order to write smarter, fully portable code, then this book is for you. Beginning with new language features, this book will help you understand the language’s mechanics and library features, and offers insight into how they work. Unlike other books, ours takes an implementation-specific, problem-solution approach that will help you quickly overcome hurdles. You will learn the core STL concepts, such as containers, algorithms, utility classes, lambda expressions, iterators, and more, while working on practical real-world recipes. These recipes will help you get the most from the STL and show you how to program in a better way. By the end of the book, you will be up to date with the latest C++17 features and save time and effort while solving tasks elegantly using the STL.
Table of Contents (18 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Replacing void* with std::any for more type safety


It can happen that we want to store items of any type in a variable. For such a variable, we then need to be able to check whether it contains anything, and if it does, we need to be able to distinguish what it contains. All this needs to happen in a type-safe manner.

In the past, we were basically able to store pointers to various objects in a void* pointer. A void typed pointer alone cannot tell us what kind of object it points to, so we would need to handcraft some kind of additional mechanism that tells us what to expect. Such code quickly leads to quirky looking and unsafe code.

Another addition of C++17 to the STL is the std::any type. It is designed to hold variables of any kind and provides facilities that enable for type-safe inspection and access to it.

In this recipe, we will play around with this utility type in order to get a feeling of it.

How to do it...

We will implement a function that tries to be able to print everything. It...