Differences between interface and abstract class in c#
In this article, I have explained the difference between an Abstract Class and an Interface in C#.
Introduction
It is little confusing when we are discussing about an abstract class and interface in C#. Some similarities and differences between an interface and an abstract class are following.
Table
| Feature |
Interface |
Abstract class |
| Multiple inheritance |
Interface can implement multiple inheritance |
It can not |
| Default implementation |
An interface has no implementation |
An abstract class can provide complete, default code and/or just the details that have to be overridden.
|
| Access Modfiers |
All interfaces are by default public and abstract |
An abstract class can contain access modifiers |
| Speed |
Requires more time to find the actual method in the corresponding classes. |
Fast |
| Homogeneity |
If various implementations only share method signatures then it is better to use Interfaces. |
If various implementations are of the same kind and use common behaviour or status then abstract class is better to use. |
| Fields and Constants |
No fields can be defined in interfaces |
An abstract class can have fields and constrants defined |