| Interfaces provide a form of multiple inheritance. A class
can extend only one other class.
Interfaces are limited to public methods and constants with
no implementation. Abstract classes can have a partial
implementation, protected parts, static methods, etc.
A Class may implement several interfaces. But in case of
abstract class, a class may extend only one abstract class.
Interfaces are slow as it requires extra indirection to to
find corresponding method in in the actual class. Abstract
classes are fast. .......................................................................... (1) An abstract class may contain complete or
incomplete methods. Interfaces can contain only the
signature of a method but no body. Thus an abstract class
can implement methods but an interface can not implement
methods.
(2) An abstract class can contain fields,
constructors, or destructors and implement properties. An
interface can not contain fields, constructors, or
destructors and it has only the property's signature but no
implementation.
(3) An abstract class cannot support multiple
inheritance, but an interface can support multiple
inheritance. Thus a class may inherit several interfaces
but only one abstract class.
(4) A class implementing an interface has to
implement all the methods of the interface, but the same is
not required in the case of an abstract Class.
(5) Various access modifiers such as abstract,
protected, internal, public, virtual, etc. are useful in
abstract Classes but not in interfaces.
(6) Abstract classes are faster than interfaces. ............................................................................... ABSTRACT CLASS:
1) we can't create object of abstract class.
2) we can declare a variable.
3) we can make normal method and abstract method.
4) we can't make method body with abstract method.
5) in derived class we can use abstract method by override
keyword.
6) we can't use multiple inheritance in abstract class.
7) Absrtact class can be extended by only one class;
Interface can be implemented by more than one class;
ie. class can inherit only one abstract class
8)Abstract classes can inherit interfaces while interfaces
cannot inherit abstract classes
but class can implement more than one interface.
9) The members of the interface are public with no
implementation. Abstract classes can have protected
parts,static methods, etc.
10)An abstract class can contain fields,
constructors, or destructors and implement properties. An
interface can not contain fields, constructors, or
destructors and it has abstractmethod,property's signature
but no implementation etc. |
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