C++: Abstract Classes vs Interfaces

What is the difference between abstract classes and interfaces in C++?

In C++, an abstract class can have both abstract methods (without implementation) and concrete methods (with implementation), while an interface is a pure abstract class that only contains abstract methods.

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

Sure! Use an abstract class when you want to provide a common base with some shared functionality, but still require derived classes to implement specific behaviors.

What about interfaces? When should I use them?

Interfaces are ideal when you want to define a contract that multiple classes can implement, ensuring they all provide specific methods without dictating how they should be implemented.

Are there any performance differences between using abstract classes and interfaces?

Generally, the performance difference is negligible, but abstract classes can have some overhead due to their ability to contain state and implementation.