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.

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Reactor

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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

A common criticism of *Design Patterns* is that the patterns only apply to message-passing object-oriented languages like **C++** or **Java**. Many see patterns as workarounds for absent language features. The reasoning behind this viewpoint being that the need for patterns is an indication that a language is somehow less
powerful.

![](/api/collection/10370001/5041597622779904/page/6522574714961920/image/4908653011795968)

There is indeed some truth to this statement. *Design Patterns* itself states it clearly:
 
**“The choice of
programming language is important because it influences one’s point of view”** ([Gamma, et al.](https://www.educative.io/courses/software-design-patterns-c/conclusion)).

The book
goes on to state that its pattern catalog assumes **“Smalltalk/C++ level language features.”** If we go for
a higher-level language than **C++**, such **Common Lisp**, we find that many design patterns don’t apply because:
* Common Lisp has a completely different design space. 
* Many patterns are internalized within the language. The Strategy pattern is internalized within first-class functions and the Visitor pattern through the generic function model in Common Lisp’s object system .

In this lesson, we will briefly explain the FIRST-CLASS ADT pattern.

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

Reflections on First-Class ADT

Criticism of Design Patterns