Difference between Abstract Class and Interface

Abstract class

• Abstract class has both Abstract methods and Non abstract methods.
• Abstract class is a class that you cannot create instance on i.e. you cannot create new object for abstract class.
• One or more class can derive the abstract class.
• If we derive some methods in abstract class in derived class we may or may not implement those methods.
• In abstract class we can use access modifiers like public, private.
• Abstract methods have both method implementation and method declaration
• Abstract class does not support multiple inheritances.
• Abstract class we can define field and constant.
• Abstract class we can use constructor or destructor.

Interface:

• In interface we should implement all the methods in Derived class.
• Interface we cannot use modifiers because by default those are public.
• Interfaces have only method declaration it’s not method implementation. It has implanted only on derived class.
• Interface support multiple inheritance.