Book Image

Hands-On Design Patterns with C++

By : Fedor G. Pikus
Book Image

Hands-On Design Patterns with C++

By: Fedor G. Pikus

Overview of this book

C++ is a general-purpose programming language designed with the goals of efficiency, performance, and flexibility in mind. 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. The focus of this book is on the design patterns that naturally lend themselves to the needs of a C++ programmer, and on the patterns that uniquely benefit from the features of C++, in particular, the generic programming. Armed with the knowledge of these patterns, you will spend less time searching for a solution to a common problem and be familiar with the solutions developed from experience, as well as their advantages and drawbacks. The other use of design patterns is as a concise and an efficient way to communicate. A pattern is a familiar and instantly recognizable solution to specific problem; through its use, sometimes with a single line of code, we can convey a considerable amount of information. The code conveys: "This is the problem we are facing, these are additional considerations that are most important in our case; hence, the following well-known solution was chosen." By the end of this book, you will have gained a comprehensive understanding of design patterns to create robust, reusable, and maintainable code.
Table of Contents (21 chapters)

Chapter 15

  • What is the Singleton pattern?

The Singleton pattern enforces the uniqueness of an object; only one instantiation of a particular object can exist in the entire program.

  • When can the Singleton pattern be used and when should it be avoided?

In a poorly designed program, a Singleton can be used as a substitute for a global variable. To justify its use, there have to be additional reasons for the uniqueness of the object. These reasons can reflect the nature of the reality that is modeled by the program (one car per driver and one Sun in the solar system) or an artificially imposed design restriction (one central source of memory for the whole program). In either case, the programmer should consider how likely it is that the requirements will change and multiple instances will be needed, and weigh it against the work necessary to maintain more complex code with multiple...