SOLID Principles

The SOLID principles constitute a set of guidelines aimed at crafting high quality software, easily maintainable, and scalable.

Initially presented by Robert C. Martin in his 2000 paper "Design Principles and Design Patterns," these principles aimed to assist developers in producing software that is comprehensible, adaptable, and extendable.

Later on, Michael Feathers further elaborated on these ideas, introducing the SOLID acronym:

S	Single Responsibility Principle (SRP)
O	Open-Closed Principle (OCP)
L	Liskov Substitution Principle (LSP)
I	Interface Segregation Principle (ISP)
D	Dependency Inversion Principle (DIP)

These principles provide developers with a framework for structuring their code, facilitating the creation of software that is agile, easily modifiable, and testable.

Adherence to SOLID principles promotes the development of code that is modular, maintainable, and capable of seamless expansion, while also streamlining collaborative efforts among developers working on a shared codebase.

But, what are they, how do we follow them?

I have always learn by example, so here they are. Simple examples written in C# so we all can learn about SOLID principles and how to implement them.

Single Responsibility Principle

"There should never be more than one reason for a class to change."

Open-Closed Principle

"Software entities should be open for extension, but closed for modification."

Liskov substitution Principle

"Functions that use pointers or references to base classes must be able to use objects of derived classes without knowing it."

Interface segregation principle

"Clients should not be forced to depend upon interfaces that they do not use."

Dependency Inversion Principle

"Depend upon abstractions, [not] concretes."