Visual Basic

returnValue = FunctionName(arg1, arg2, … argn)

<scope> Function FunctionName(arg1 As Type, arg2 As Type, … argn As Type) As ReturnType

   'define the return value to use
   Dim retVal as ReturnType

   'perform what ever calculations you need to do

   'set the return value
   retVal = answerToCalculation

   Return ReturnType 'if you are using VB.NET
   FunctionName = answerToCalulation 'if you are using VB6

End Function

Public Class Animal
    Public Sub Bark()
        If TypeOf(Me) Is Dog Then
            Console.WriteLine("Bark!")
        Else
            Console.WriteLine("I can't bark!")
        End If
    End Sub
End Class
 
Public Class Dog : Inherits Animal
    
End Class

Public Class Animal
    Public Overridable Sub Bark()
        Console.WriteLine("I can't bark!")
    End Sub
End Class
 
Public Class Dog : Inherits Animal
    Public Overrides Sub Bark()
        Console.WriteLine("Bark!")
    End Sub
End Class

Public MustInherit Class Animal
    Public MustOverride Sub Bark()
End Class
 
Public Class Dog : Animal
    Public Overrides Sub Bark()
        Console.WriteLine("Bark!")
    End Sub
End Class