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

Terminating iterations over ranges with iterator sentinels


Both STL algorithms and the range-based for loop assume that the begin and end positions of the iteration are known in advance. In some situations, however, it is hardly possible to know the end position before reaching it by iteration.

A very simple example for this is iterating over plain C-Style strings, the length of which is not known before runtime. The code which iterates over such strings usually looks like this:

for (const char *c_ponter = some_c_string; *c_pointer != '\0'; ++c_pointer) {
    const char c = *c_pointer;
    // do something with c
}

The only way to put this into a range-based for loop seems to be wrapping it into an std::string, which has begin() and end() functions:

for (char c : std::string(some_c_string)) { /* do something with c */ }

However, the constructor of std::string will iterate over the whole string before our for loop can iterate over it. Since C++17, we also have std::string_view, but its constructor...