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

Managing dependencies between entities in a software system is crucial to a solid design. In the [previous chapter](https://www.educative.io/courses/software-design-patterns-c/implementing-the-strategy-pattern), we had a look at the **open-closed principle**. Now we’ll turn to another principle for dependency
management and illustrate how both of these principles may be realized in C using the **Observer** pattern.

In this lesson, we will explain the theory of the observer 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

Theory of the Observer Pattern