Book Image

Modern C++ Programming Cookbook - Third Edition

By : Marius Bancila
Book Image

Modern C++ Programming Cookbook - Third Edition

By: Marius Bancila

Overview of this book

The updated third edition of Modern C++ Programming Cookbook addresses the latest features of C++23, such as the stack library, the expected and mdspan types, span buffers, formatting library improvements, and updates to the ranges library. It also gets into more C++20 topics not previously covered, such as sync output streams and source_location. The book is organized in the form of practical recipes covering a wide range of real-world problems. It gets into the details of all the core concepts of 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. You will cover the performance aspects of programming in depth, and learning to write fast and lean code with the help of best practices. You will explore useful patterns and the implementation of many idioms, including pimpl, named parameter, attorney-client, and the factory pattern. A chapter dedicated to unit testing introduces you to three of the most widely used libraries for C++: Boost.Test, Google Test, and Catch2. By the end of this modern C++ programming book, you will be able to effectively leverage the features and techniques of C++11/14/17/20/23 programming to enhance the performance, scalability, and efficiency of your applications.
Table of Contents (15 chapters)
13
Other Books You May Enjoy
14
Index

Handling friendship with the attorney-client idiom

Granting functions and classes access to the non-public parts of a class with a friend declaration is usually seen as a sign of bad design, as friendship breaks encapsulation and ties classes and functions. Friends, whether they are classes or functions, get access to all the private members of a class, although they may only need to access parts of it.

The attorney-client idiom provides a simple mechanism to restrict friends access to only designated private members of a class.

Getting ready

To demonstrate how to implement this idiom, we will consider the following classes: Client, which has some private member data and functions (the public interface is not important here), and Friend, which is supposed to access only parts of the private details, for instance, data1 and action1(), but has access to everything:

class Client
{
  int data_1;
  int data_2;
  void action1() {}
  void action2() {}
  friend class Friend...