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Virtual methods in C#

Def: A virtual method is a method that can be redefined in derived classes. A virtual method has an implementation in a base class as well as derived the class. It is used when a method's basic functionality is the same but sometimes more functionality is needed in the derived class. A virtual method is created in the base class that can be overriden in the derived class. We create a virtual method in the base class using the virtual keyword and that method is overriden in the derived class using the override keyword.

Descryp: When a method is declared as a virtual method in a base class then that method can be defined in a base class and it is optional for the derived class to override that method. The overriding method also provides more than one form for a method. Hence it is also an example for polymorphism.

When a method is declared as a virtual method in a base class and that method has the same definition in a derived class then there is no need to override it in the derived class. But when a virtual method has a different definition in the base class and the derived class then there is a need to override it in the derived class. When a virtual method is invoked, the run-time type of the object is checked for an overriding member. The overriding member in the most derived class is called, which might be the original member, if no derived class has overridden the member.

Program cant use private virtual method, because virtual or abstract members cannot be private. And after compiling you’ll have error.

Ex: public class Shape;

{ int x,y;

Public virtual string Draw(string Figure)

{Cons.wr.(Figure);}

}

Class Rectangle: Shape

{ public override string Draw(string Name)

{Cons.Wr(“Rectangle”);}

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