Book Image

Hands-On Design Patterns with C++ (Second Edition) - Second Edition

By : Fedor G. Pikus
5 (1)
Book Image

Hands-On Design Patterns with C++ (Second Edition) - Second Edition

5 (1)
By: Fedor G. Pikus

Overview of this book

C++ is a general-purpose programming language designed for efficiency, performance, and flexibility. Design patterns are commonly accepted solutions to well-recognized design problems. In essence, they are a library of reusable components, only for software architecture, and not for a concrete implementation. This book helps you focus on the design patterns that naturally adapt to your needs, and on the patterns that uniquely benefit from the features of C++. Armed with the knowledge of these patterns, you’ll spend less time searching for solutions to common problems and tackle challenges with the solutions developed from experience. You’ll also explore that design patterns are a concise and efficient way to communicate, as patterns are a familiar and recognizable solution to a specific problem and can convey a considerable amount of information with a single line of code. By the end of this book, you’ll have a deep understanding of how to use design patterns to write maintainable, robust, and reusable software.
Table of Contents (26 chapters)
1
Part 1: Getting Started with C++ Features and Concepts
5
Part 2: Common C++ Idioms
10
Part 3: C++ Design Patterns
18
Part 4: Advanced C++ Design Patterns

Chapter 17, The Visitor Pattern and Multiple Dispatch

  1. The Visitor pattern provides a way to separate the implementation of algorithms from the objects they operate on; in other words, it is a way to add operations to classes without modifying them by writing new member functions.
  2. The Visitor pattern allows us to extend the functionality of class hierarchies. It can be used when the source code of the class is not available for modification or when such modifications would be difficult to maintain.
  3. Double dispatch is the process of dispatching a function call (selecting the algorithm to run) based on two factors. Double dispatch can be implemented at runtime using the Visitor pattern (virtual functions provide the single dispatch) or at compile time using templates or compile-time visitors.
  4. The classic visitor has a circular dependency between the visitor class hierarchy and the visitable class hierarchy. While the visitable classes do not need to be edited when a new...