Scenario of Classes

Deepak Dwij

15y1.8kVisual Basic .NET

Hi,
I have learned various class, What is the real life scenario of abstract class,sealed class?

2 Replies

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Vulpes15y ago
A classic real world example of an abstract class is Animal.

The Animal class may have an abstract method MakeNoise.

However, specific Animals will make different noises - dogs bark, cats meow, pigs grunt etc - and so the derived classes for these Animals will need to override the MakeNoise method to make the noise which applies to them.

A class should be sealed if it makes no sense for any other class to inherit from it.

Suppose for example you were writing a Photon class.

As far as I know, there's only one kind of Photon so it wouldn't make sense to inherit from it. The Photon class should therefore be sealed.
Satyapriya Nayak15y ago
Hi Deepak,

Abstract class is a class that can not be instantiated, it exists extensively for inheritance and it must be inherited. There are scenarios in which it is useful to define classes that is not intended to instantiate; because such classes normally are used as base-classes in inheritance hierarchies, we call such classes abstract classes.

Abstract classes cannot be used to instantiate objects; because abstract classes are incomplete, it may contain only definition of the properties or methods and derived classes that inherit this implements it's properties or methods.

Static, Value Types & interface doesn't support abstract modifiers. Static members cannot be abstract. Classes with abstract member must also be abstract.

For detailed example, read this article http://www.dotnetfunda.com/articles/article467-abstract-class--explained.aspx

sealed class:- We cannot inherit from this class.

For detailed example, read this article

http://www.c-sharpcorner.com/UploadFile/mahesh/SealedClasses11142005063733AM/SealedClasses.aspx

Thanks