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 simple RPN calculator with std::stack


The std::stack is an adapter class which lets the user push objects onto it like on a real stack of objects, and pop objects down from it again. In this section, we construct a reverse polish notation (RPN) calculator around that data structure, in order to show how to use it.

The RPN is a notation that can be used to express mathematical expressions in a way that is really simple to parse. In RPN, 1 + 2 is 1 2 +. Operands first, then the operation. Another example: (1 + 2) * 3 would be 1 2 + 3 * in RPN and that already shows why it is easier to parse, as we do not need parentheses to define subexpressions.

How to do it...

In this section, we will read a mathematical expression in RPN from the standard input, and then feed it into a function that evaluates it. In the end, we print the numeric result back to the user.

  1. We will use a lot of helpers from the STL, so there are a few includes:
      #include <iostream>
      #include <stack...