According to the Open-Closed principle, a program should be open to development and closed to change. — I. Introduction SOLID principles allow writing “clean code” in object-oriented programming. Solid principles enable faster editing of the developed project. Solid principles require 5 basic rules. · S stands for SRP (Single Responsibility Principle) · O stands for OCP (Open Closed Principle) · L stands for LSP (Liskov Substitution Principle)