By: Suresh Dasari Apr 6, 2010
In previous article I explained complete OOPS Concept. Now I will explain differences between Abstract classes and Interfaces.
An Abstract class without any implementation just looks like an Interface; however there are lot of differences than similarities between an Abstract class and an Interface. Let's explain both concepts and compare their similarities and differences.
What is an Abstract Class?
An abstract class is a special kind of class that cannot be instantiated. So the question is why we need a class that cannot be instantiated? An abstract class is only to be sub-classed (inherited from). In other words, it only allows other classes to inherit from it but cannot be instantiated. The advantage is that it enforces certain hierarchies for all the subclasses. In simple words, it is a kind of contract that forces all the subclasses to carry on the same hierarchies or standards.
What is an Interface
An interface is not a class. It is an entity that is defined by the word Interface. An interface has no implementation; it only has the signature or in other words, just the definition of the methods without the body. As one of the similarities to Abstract class, it is a contract that is used to define hierarchies for all subclasses or it defines specific set of methods and their arguments. The main difference between them is that a class can implement more than one interface but can only inherit from one abstract class. Since C# doesn't support multiple inheritance, interfaces are used to implement multiple inheritance.
When we create an interface, we are basically creating a set of methods without any implementation that must be overridden by the implemented classes. The advantage is that it provides a way for a class to be a part of two classes: one from inheritance hierarchy and one from the interface.
When we create an abstract class, we are creating a base class that might have one or more completed methods but at least one or more methods are left uncompleted and declared abstract. If all the methods of an abstract class are uncompleted then it is same as an interface. The purpose of an abstract class is to provide a base class definition for how a set of derived classes will work and then allow the programmers to fill the implementation in the derived classes.
I have explained the differences between an abstract class and an interface.
I think it helps you
Other Related Posts
- Interview Questions in ASP.NET,C#.NET,SQL Server,.NET Framework
- Asp.net insert, Edit, update, delete data in gridview
- 3 tier architecture example in asp.net with C#
- Introduction to Object Oriented Programming Concepts (OOPS) in C#.net
- Simple login form example in asp.net Check Username and Password availability in database
- Introduction to WCF - WCF tutorial | WCF Tutorial - Windows Communication Foundation | WCF Example | WCF Sample code in asp.net 3.5 | Basic WCF Tutorial for Beginners
- how to insert images into database and how to retrieve and bind images to gridview using asp.net (or) save and retrieve images from database using asp.net
- jQuery 360 Degrees Image Display Plugins Examples with Tutorial
- Asp.net WebService or Creating and Consuming WebService in asp.net or Create and call webservice in asp.net or how to create webservice and how to use webservice in asp.net
- Best Login Page Design in HTML, CSS with Source Code