Prerequisites — OOPs fundamentals

Solid Principles:

S — Single Responsibility Principle

O — Open/Closed Principle

L — Liskov Substitution Principle

I — Interface Segmented Principle

D — Dependency Inversion Principle

Single Responsibility Principle : A Class should have only one reason to change.

Open/Closed Principle : Open for extension but closed for modification.

Liskov Substitution Principle : If Class B is the subtype of Class A , then we should be able to replace object of A with B without breaking the behaviour of the program.

Interface Segmented Principle : Interfaces should be such , that client should not implement unnecessary functions they do not need.

Dependency Inversion Principle : Class should not depend on interfaces , rather than concrete classes.

Advantages of following these principles:

Avoid Duplicate Code.
Easy to maintain.
Easy to understand.
Flexible software.
Reduces complexity.