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

Safely signalizing failure with std::optional


When a program communicates with the outside world and relies on values it gets from there, then all kinds of failures can happen.

This means that whenever we write a function that ought to return a value, but that can also possibly fail, then this must be reflected in some change of the function interface. We have several possibilities. Let's see how we can design the interface of a function that will return a string, but that could also fail:

  • Use a success-indicating return value and output parameters: bool get_string(string&);
  • Return a pointer (or a smart pointer) that can be set to nullptr if there is a failure: string* get_string();
  • Throw an exception in the case of failure and leave the function signature very simple: string get_string();

All these approaches have different advantages and disadvantages. Since C++17, there is a new type that can be used to solve such a problem in a different way: std::optional. The notion of an optional value...