What principles does SOLID include?

S - Single Responsibility Principle. A class should have only one reason to change.

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

L - Liskov Substitution Principle. Subtypes should be fully interchangeable with their base types.

I - Interface Segregation Principle. Clients should not depend on interfaces they do not use. It's better to have many small, specific interfaces than one large, general interface.

D - Dependency Inversion Principle. Higher-level modules should not depend on lower-level modules. Both should depend on abstractions. Abstractions should not depend on details. Details should depend on abstractions.