C# is a superior language that programmers can use to design some of the best applications, software, and even integrated systems. In an interview regarding a C# related job, it is hard to miss the question on implementing a C# abstract class. We have, therefore, in this article compiled the best answers to help you ace your interview.
What is a C# Abstract Class?
An abstract class in C# is a particular type of class which cannot be instantiated and acts as the base class for other classes. The members of an abstract class, usually marked as abstract, have to be implemented by derived classes.
In simpler words, it is a class with an abstract modifier. Abstract modifiers indicate that the class, method, index or event being modified misses or has an incomplete implementation. The primary purpose of the C# abstract class is to give basic or default functionality or a standard functionality that several derived classes can use together and override.
For instance, a class library may express an abstract class utilized as a parameter to many of its functions, and usually requires programmers using that particular library to give their implementation of the class by establishing an abstract class. An example of an abstract class in C# is ‘System.IO.Stream’ whose implementation is ‘System.IO.FileStream’.
What Are the Features of Abstract Classes?
- They contain both abstract and non-abstract members
- They cannot be sealed because the sealed modifier will, therefore, prevent it from being inherited, yet the abstract modifier needs a class to be inherited
- They can be inherited from a class as well as one or multiple interfaces.
- They contain access modifiers such as private and protected with their members.
- They can carry variables like constants and fields.
- They can be described as implicitly a virtual method
How to Implement an Abstract Class in C#
Here’s an example of an implementation of an abstract class:
abstract class DishWasher
// write the code to initialize the class here.
abstract public void Clean();
abstract public void Wash(int load_Size);
abstract public long Dry(int speed);
In the example shown above, the C# abstract class is declared with a single implemented method as well as three other methods which aren’t implemented. Therefore, a class which inherits from this class will have to implement the Clean, Wash and Dry methods. An example of that class would be:
class MyDishWasher: DishWasher
public MyDishWasher ()
// the initialization code is input here.
override public void Clean()
// the Clean code is written here.
override public void Wash(int loadSize)
// Add rinse code here.
override public long Dry(int speed)
// Dry code here.
During the implementation of an abstract class in C#, each abstract method within the given class has to be implemented too. Consequently, each of the applied methods must be given the same number and type of arguments as well as a similar return value, just like the specified method within the abstract class.