Interface

Question

Hi What is the difference between Interface class and an abstract class. In both classes we can not define any function and we can derived any class from both type of class. where we should use Interface class and abstract classes.

sacresp · Answer

You can derive from multiple interfaces but not from many classes. Or actually one says implement an interface not derive. (Interfaces are not classes)

seamus · Answer

An interface can only declare constants and instance method signatures it cannot implement default behavior. An abstract class has at least one instance method that is declared abstract which must be implemented by all subclasses. It can also have additional instance methods that implement default behavior.