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

Template instantiations

The template name is not a type and cannot be used to declare a variable or call a function. To create a type or a function, the template must be instantiated. Most of the time, templates are instantiated implicitly when they are used. We will again start with function templates.

Function templates

To use a function template to generate a function, we have to specify which types should be used for all template type parameters. We can just specify the types directly:

template <typename T> T half(T x) { return x/2; }
int i = half<int>(5);

This instantiates the half function template with the int type. The type is explicitly specified; we could call the function with an argument of another type, as long as it is convertible to the type we requested:

double x = half<double>(5);

Even though the argument is an int, the instantiation is that of half<double>, and the return type is double. The integer value 5 is implicitly converted...