Abstract class: - It is an
incomplete class whose object cannot be created. It contains the skeleton of the
method, which is implemented by derived class. The abstract class is prefixed by
the keyword MustInherit. The methods with in the class are prefixed by
MustOverride keyword. The derived class procedure, which implements the abstract
class, is prefixed by Overrides keyword.
Program
Public
Class Form1
Private Sub
Button1_Click(ByVal sender
As System.Object,
ByVal e As System.EventArgs)
Handles Button1.Click
Dim a As
New raj1
a.ravi("Rahul")
End Sub
Public
MustInherit Class raj
Public
MustOverride Sub ravi(ByVal
s As String)
End Class
Public
Class raj1
Inherits raj
Public
Overrides Sub ravi(ByVal
s As String)
MsgBox("Hello:" & s)
End Sub
End
Class
End
Class
Interface: - It is a
specification of class members not the implementation of members.
It is the substitute of
multiple inheritance more than one interface can be implemented by a single
class. The members with in the interface are not defined. It is public by
default. Variables cannot be declared within the interface. Both sub procedure
and function procedure can be stored in the interface.
Program
Public
Class Form2
Private Sub
Button1_Click(ByVal sender
As System.Object,
ByVal e As System.EventArgs)
Handles Button1.Click
Dim a As
New raj1
a.sagar(25)
a.amit("Abhijeet")
MsgBox(a.rahul(10, 20))
End Sub
Public
Interface raj
Sub sagar(ByVal
x As Integer)
Sub amit(ByVal
s As String)
Function rahul(ByVal
x As Integer,
ByVal y As
Integer)
End Interface
Public
Class raj1
Implements raj
Public Sub
amit(ByVal s As
String) Implements
raj.amit
MsgBox("Hello:" & s)
End Sub
Public
Function rahul(ByVal
x As Integer,
ByVal y As
Integer) As
Object Implements
raj.rahul
Dim z
As Integer
z = x + y
Return z
End
Function
Public Sub sagar(ByVal
x As Integer)
Implements raj.sagar
MsgBox(x)
End Sub
End
Class
End
Class
Thanks for reading