Book Image

Modern C++ Programming Cookbook

By : Marius Bancila
Book Image

Modern C++ Programming Cookbook

By: Marius Bancila

Overview of this book

C++ is one of the most widely used programming languages. Fast, efficient, and flexible, it is used to solve many problems. The latest versions of C++ have seen programmers change the way they code, giving up on the old-fashioned C-style programming and adopting modern C++ instead. Beginning with the modern language features, each recipe addresses a specific problem, with a discussion that explains the solution and offers insight into how it works. You will learn major concepts about the core programming language as well as common tasks faced while building a wide variety of software. You will learn about concepts such as concurrency, performance, meta-programming, lambda expressions, regular expressions, testing, and many more in the form of recipes. These recipes will ensure you can make your applications robust and fast. By the end of the book, you will understand the newer aspects of C++11/14/17 and will be able to overcome tasks that are time-consuming or would break your stride while developing.
Table of Contents (19 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Using the indirection pattern for preprocessor stringification and concatenation


The C++ preprocessor provides two operators for transforming identifiers into strings and concatenating identifiers together. The first one, operator #, is called the stringizing operator, and the second one, operator ##, is called the token-pasting, merging, or concatenating operator. Although their use is limited to some particular cases, it is important to understand how they work.

Getting ready

For this recipe, you need to know how to define macros using the preprocessor directive #define.

How to do it...

To create a string from an identifier using the preprocessor's operator#, use the following pattern:

  1. Define a helper macro taking one argument that expands to # followed by the argument:
        #define MAKE_STR2(x) #x 
  1. Define the macro you want to use, taking one argument that expands to the helper macro:
        #define MAKE_STR(x) MAKE_STR2(x)

To concatenate identifiers together using the preprocessor's operator...