Open-Closed principle

Introduction

The open-closed principle is one the first five principles of software design, by Robert C. Martin.
The five principles where stated as follows:

Single Responsibility PrincipleOpen-Closed PrincipleLiskov Substitution PrincipleInterface Segregation PrincipleDependency Inversion principle

They are also referred to as the SOLID design principles. These principles are necessary for the production of clear, clean, easily maintainable and extensible code.
In this article, we will to...