Book Image

Modern C++ Programming Cookbook - Second Edition

By : Marius Bancila
5 (1)
Book Image

Modern C++ Programming Cookbook - Second Edition

5 (1)
By: Marius Bancila

Overview of this book

C++ has come a long way to be one of the most widely used general-purpose languages that is fast, efficient, and high-performance at its core. The updated second edition of Modern C++ Programming Cookbook addresses the latest features of C++20, such as modules, concepts, coroutines, and the many additions to the standard library, including ranges and text formatting. The book is organized in the form of practical recipes covering a wide range of problems faced by modern developers. The book also delves into the details of all the core concepts in modern C++ programming, such as functions and classes, iterators and algorithms, streams and the file system, threading and concurrency, smart pointers and move semantics, and many others. It goes into the performance aspects of programming in depth, teaching developers how to write fast and lean code with the help of best practices. Furthermore, the book explores useful patterns and delves into the implementation of many idioms, including pimpl, named parameter, and attorney-client, teaching techniques such as avoiding repetition with the factory pattern. There is also a chapter dedicated to unit testing, where you are introduced to three of the most widely used libraries for C++: Boost.Test, Google Test, and Catch2. By the end of the book, you will be able to effectively leverage the features and techniques of C++11/14/17/20 programming to enhance the performance, scalability, and efficiency of your applications.
Table of Contents (16 chapters)
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Removing content from a file

Operations such as copying, renaming, moving, or deleting files are directly provided by the filesystem library. However, when it comes to removing content from a file, you must perform explicit actions.

Regardless of whether you need to do this for text or binary files, you must implement the following pattern:

  1. Create a temporary file.
  2. Copy only the content that you want from the original file to the temporary file.
  3. Delete the original file.
  4. Rename/move the temporary file to the name/location of the original file.

In this recipe, we will learn how to implement this pattern for a text file.

Getting ready

For the purpose of this recipe, we will consider removing empty lines, or lines that start with a semicolon (;), from a text file. For this example, we will have an initial file, called sample.dat, that contains the names of Shakespeare's plays but also empty lines and lines that start with a semicolon...