"----Abstaract Class" in Oops Example in VB.NET

'it contains method which can have impementation or without implementation

'if without imp then it must be override in child clss

Public MustInherit Class AbstractClass

'declaring an abstract class with MustInherit keyword

Public MustOverride Function Add() As Integer

Public MustOverride Function Mul() As Integer

'declaring two abstract members with MustOverride keyword

End Class

Public Class AbstractOne

Inherits AbstractClass

'implementing the abstract class by inheriting

Dim i As Integer = 20

Dim j As Integer = 30

'declaring two integers

Public Overrides Function Add() As Integer

Return i + j

End Function

'implementing the add method

Public Overrides Function Mul() As Integer

Return i * j

End Function

'implementing the mul method

End Class

Sub Main()

Dim abs As New AbstractOne()

'creating an instance of AbstractOne

Console.WriteLine(

"Sum is" & " " & abs.Add().ToString)

Console.WriteLine(

"Multiplication is" & " " & abs.Mul())

MsgBox(

"Multiplication is" & " " & abs.Mul())

MsgBox(

"Addition is" & " " & abs.Add())

'displaying output

Read()

End Sub

 

Out Put :

Sum is 50
Multiplication is 600