Can you explain the principles underlying the SOLID concept in object-oriented programming?

SOLID principles are five fundamental rules of object-oriented design aimed at creating flexible and maintainable software:

• S (Single Responsibility Principle) — a class should have only one reason to change, meaning it should perform only one task.
• O (Open/Closed Principle) — software entities should be open for extension but closed for modification.
• L (Liskov Substitution Principle) — objects of subclasses should be interchangeable with objects of the superclass without affecting the correctness of the program.
• I (Interface Segregation Principle) — clients should not depend on interfaces they do not use.
• D (Dependency Inversion Principle) — high-level modules should not depend on low-level modules; both should depend on abstractions.

These principles help create code that is easier to test, extend, and maintain.