What are some common mistakes when using abstract classes in C++?

What are some common mistakes when using abstract classes in C++?

Some common mistakes include not declaring pure virtual functions, attempting to instantiate abstract classes, and forgetting to override virtual functions in derived classes.

Can you explain why we can't instantiate abstract classes?

Abstract classes are meant to provide a base for other classes. They contain at least one pure virtual function, making them incomplete and thus cannot be instantiated.

What happens if I forget to override a pure virtual function?

If you forget to override a pure virtual function in a derived class, that derived class will also become abstract, and you won't be able to instantiate it.

Are there any best practices for using abstract classes?

Yes, always ensure that your abstract classes have a clear purpose, provide meaningful default implementations when possible, and document the expected behavior of derived classes.