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

Comfortably pretty printing numbers differently per context on the fly


In the last recipe, we learned how to format the output with output streams. And while doing the same, we realized two facts:

  • Most I/O manipulators are sticky, so we have to revert their effect after use in order to not tamper with other unrelated code, which also prints
  • It can be very tedious and does not look very readable if we have to set up long chains of I/O manipulators in order to get only a few variables printed with specific formatting

A lot of people do not like I/O streams for such reasons, and even in C++, they still use printf for formatting their strings.

In this recipe, we will see how to format types on the fly without too much I/O manipulator noise in our code.

How to do it...

We are going to implement a class, format_guard, which can automatically revert any format setting. Additionally, we add a wrapper type, which can contain any value, but when it is printed, it gets special formatting without burdening...