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)

When to use type erasure, and when to avoid it

We have already seen an example where type erasure was used very successfully—the std::shared_ptr shared pointer. On the other hand, the standard library authors did not use this technique when they implemented std::unique_ptr, and not because it is any more difficult (our simple smartptr is, in fact, a lot closer to std::unique_ptr than std::shared_ptr, since it does not do any reference counting).

Then there was the unsuccessful attempt to type-erase the sort and related functions, which ended in a complex mess that was cleaned up once and for all by letting the compiler deduce the right types, instead of erasing them. We could do with some guidelines for when to consider type erasure. There are two types of issues to keep in mind—design considerations and performance considerations.

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