Book Image

Modern C++ Programming Cookbook - Third Edition

By : Marius Bancila
Book Image

Modern C++ Programming Cookbook - Third Edition

By: Marius Bancila

Overview of this book

The updated third edition of Modern C++ Programming Cookbook addresses the latest features of C++23, such as the stack library, the expected and mdspan types, span buffers, formatting library improvements, and updates to the ranges library. It also gets into more C++20 topics not previously covered, such as sync output streams and source_location. The book is organized in the form of practical recipes covering a wide range of real-world problems. It gets into the details of all the core concepts of 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. You will cover the performance aspects of programming in depth, and learning to write fast and lean code with the help of best practices. You will explore useful patterns and the implementation of many idioms, including pimpl, named parameter, attorney-client, and the factory pattern. A chapter dedicated to unit testing introduces you to three of the most widely used libraries for C++: Boost.Test, Google Test, and Catch2. By the end of this modern C++ programming book, you will be able to effectively leverage the features and techniques of C++11/14/17/20/23 programming to enhance the performance, scalability, and efficiency of your applications.
Table of Contents (15 chapters)
13
Other Books You May Enjoy
14
Index

Using fold expressions to simplify variadic function templates

In this chapter, we are discussing folding several times; this is an operation that applies a binary function to a range of values to produce a single value. We have seen this when we discussed variadic function templates, and will see it again with higher-order functions. It turns out there is a significant number of cases where the expansion of a parameter pack in variadic function templates is basically a folding operation. To simplify writing such variadic function templates, C++17 introduced fold expressions, which fold an expansion of a parameter pack over a binary operator. In this recipe, we will learn how to use fold expressions to simplify writing variadic function templates.

Getting ready

The examples in this recipe are based on the variadic function template add (), which we wrote in the previous recipe, Writing a function template with a variable number of arguments. That implementation is a left-folding operation...