What are the best practices for using abstract classes in programming?

What are the best practices for using abstract classes in programming?

When using abstract classes, ensure they define a clear contract for subclasses, promote code reuse, and avoid unnecessary complexity.

Can you give an example of when to use an abstract class?

Sure! Use an abstract class when you have a base class that should not be instantiated on its own, like a 'Shape' class with methods like 'draw' that must be implemented by subclasses.

What are the common mistakes to avoid with abstract classes?

Common mistakes include making abstract classes too specific, not providing enough abstract methods, or using them when interfaces would be more appropriate.

How do abstract classes differ from interfaces?

Abstract classes can provide some implementation and state, while interfaces only define methods without any implementation. You can also inherit from only one abstract class but implement multiple interfaces.

Are there any performance considerations when using abstract classes?

Generally, the performance impact is minimal, but excessive use of abstraction can lead to more complex hierarchies, which might affect maintainability.