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)

CRTP and static polymorphism

Since CRTP allows us to override base class functions with those of the derived class, it implements polymorphic behavior. The key difference is that polymorphism happens at compile time, not at runtime.

Compile-time polymorphism

As we have just seen, CRTP can be used to allow the derived class to customize the behavior of the base class:

template <typename D> class B {
public:
...
void f(int i) { static_cast<D*>(this)->f(i); }
protected:
int i_;
};
class D : public B<D> {
public:
void f(int i) { i_ += i; }
};

If the base class B::f() method is called, it dispatches the call to the derived class method for the real derived class, just like a virtual function...