In my last article I posted about “What is APIE?“, if you haven’t read this yet and don’t know what APIE is, I recommend reading that article first.
Just like APIE states the 4 basic concepts of OOP, SOLID defines 5 OOP principles which you should always follow when writing code. The letters stand for Single responsibility, Open-closed, Liskov substitution, Interface segregation and Dependency inversion. As much as all of these principles help in achieving a maintainable code base, the Open-closed and Interface segregation principles aren’t as useful as the others in my opinion as they’re harder to implement effectively and sometimes don’t give much benefit. Regardless I will explain what you need to know about each of these.