Book Image

C++20 STL Cookbook

By : Bill Weinman
Book Image

C++20 STL Cookbook

By: Bill Weinman

Overview of this book

Fast, efficient, and flexible, the C++ programming language has come a long way and is used in every area of the industry to solve many problems. The latest version C++20 will see programmers change the way they code as it brings a whole array of features enabling the quick deployment of applications. This book will get you up and running with using the STL in the best way possible. Beginning with new language features in C++20, this book will help you understand the language's mechanics and library features and offer insights into how they work. Unlike other books, the C++20 STL Cookbook takes an implementation-specific, problem-solution approach that will help you overcome hurdles quickly. You'll learn core STL concepts, such as containers, algorithms, utility classes, lambda expressions, iterators, and more, while working on real-world recipes. This book is a reference guide for using the C++ STL with its latest capabilities and exploring the cutting-edge features in functional programming and lambda expressions. By the end of the book C++20 book, you'll be able to leverage the latest C++ features and save time and effort while solving tasks elegantly using the STL.
Table of Contents (13 chapters)

Run STL algorithms in parallel with execution policies

Beginning with C++17, many of the standard STL algorithms can run with parallel execution. This feature allows an algorithm to split its work into sub-tasks to run simultaneously on multiple cores. These algorithms accept an execution policy object that specifies the kind of parallelism applied to the algorithm. This feature requires hardware support.

How to do it…

Execution policies are defined in the <execution> header and in the std::execution namespace. In this recipe, we will test the available policies using the std::transform() algorithm:

  • For timing purposes, we'll use the duration object with the std::milli ratio so that we can measure in milliseconds:
    using dur_t = duration<double, std::milli>;
  • For demonstration purposes, we'll start with a vector of int with 10 million random values:
    int main() {
        std::vector<unsigned> v(10 * 1000 * 1000);