OOP and SOLID Principles

Abstraction: objects, classes, and variables
Encapsulation: private, public, protected
Inheritance: new classes share some of the attributes of existing classes (parent, child class, extends)
Polymorphism: method overloading, method overriding

S: Single Responsibility Principle
- A class should have only one job.
O: Open-Closed Principle
- Software entities (Classes, modules, functions) should be open for extension, not modification.
L: Liskov Substitution Principle
- A sub-class must be substitutable for its super-class.
I: Interface Segregation Principle
- Make fine grained interfaces that are client specific.
D: Dependency Inversion Principle
- High-level modules should not depend upon low-level modules. Both should depend upon abstractions.
- Abstractions should not depend on details. Details should depend upon abstractions.