Can you list and describe the key principles included in the SOLID concept?

SOLID is a set of five principles of object-oriented programming aimed at creating flexible, extendable, and maintainable systems:

1. S — Single Responsibility Principle: A class should have only one reason to change, meaning it should perform a single specific task.

2. O — Open/Closed Principle: Software entities should be open for extension but closed for modification.

3. L — Liskov Substitution Principle: Subclass objects should be interchangeable with superclass objects without affecting the correctness of the program.

4. I — Interface Segregation Principle: Clients should not depend on interfaces they do not use; it is better to have several specific interfaces than one general-purpose interface.

5. D — Dependency Inversion Principle: High-level modules should not depend on low-level modules; both should depend on abstractions. Abstractions should not depend on details; details should depend on abstractions.

These principles help write code that is easier to test, maintain, and extend.