What are SOLID principles?

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

1. Single Responsibility Principle: A class should have only one reason to change.
2. Open/Closed Principle: Software entities (classes, modules, functions, etc.) should be open for extension but closed for modification.
3. Liskov Substitution Principle: Objects in a program should be replaceable with instances of their subtypes without altering the correctness of the program.
4. Interface Segregation Principle: Many client-specific interfaces are better than one general-purpose interface.
5. 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.

Applying SOLID helps reduce coupling and increase cohesion in code, making it more resilient to changes.