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

Implementing a dictionary merging tool


Imagine that we have a sorted list of things, and someone else comes up with another sorted list of things, and we want to share the lists with each other. The best idea is to combine both the lists. The combination of both the lists should be sorted too, as this way, it is easy to look it up for specific items.

Such an operation is also called a merge. In order to merge two sorted ranges of items, we would intuitively create a new range and feed it with items from both the lists. For every item transfer, we would have to compare the frontmost items of our input ranges in order to always select the smallest one from what is left from the input. Otherwise, the output range would not be sorted any longer. The following diagram illustrates it better:

The std::merge algorithm can do exactly that for us, so we do not need to fiddle around too much. In this section, we will see how to use the algorithm.

How to do it...

We are going to build up a cheap dictionary...