Gain insights into software design patterns in C, explore their implementation, discover underlying principles, and learn to build a vocabulary for better communication and coding practices.

c.tar.gz

main+customer.c

main+customer.c-copy

watches

customers

observer

Reactor

Reactor-copy

observer-copy

Software design patterns are a valuable tool in any software developer's skill set. However, most design patterns are described in the context of an object-oriented programming language such as C++ or Java. The C language is sadly absent in the pattern literature. This course is here to change that by demonstrating that it is possible to use patterns in C programs and how it adds benefits to C programmers. You will learn why design patterns are more of a communication tool than technical solutions, and how patterns let you build and share a common vocabulary that simplifies communication.

The course presents a number of patterns and explains how to implement them in C. Each pattern is introduced via the problem it solves and the domains where the pattern can be used. We also discuss the underlying design principles as well as the trade-offs when applying the pattern. Finally, the course covers a set of coding idioms that will guide you when applying design patterns in C.

Software Design Patterns in C

**ADT** stands for **Abstract Data Type** and it is a set of values and operations on these values. When we have many unique instances of ADT, it is considered first-class.


It is similar to the interface listed example mentioned in the previous section. However, the data
type in the example is not abstract as it fails to hide its implementation details. To make ADT truly
abstract, we have to utilize a powerful feature of C: the ability to specify incomplete types.

The C standard (C 1999) allows us to declare objects of incomplete types in a context where their sizes
aren’t needed. In our example implementation, we are interested in the possibility to specify a pointer to an incomplete type.
> Note: **The pointer itself is not of an
incomplete type.**


In this lesson, we will explain the implementation of the  First-Class ADT pattern in the C language.

Introduction to Pattern in C

The First-Class ADT Pattern

The State Pattern

The Strategy Pattern

The Observer Pattern

The Reactor Pattern

Idiomatic Expressions

Conclusion

Implementing the First-Class ADT Pattern

Definition of a FIRST-CLASS ADT

Incomplete types