Visual Basic .Net

Module Polymorph
   Sub Main()
      ' create some shape instances
      Dim i
      Dim scribble(2) As Shape
      scribble(0) = New Rectangle(10, 20, 5, 6)
      scribble(1) = New Circle(15, 25, 8)

      ' iterate through the list and handle shapes polymorphically
      For i = 0 To UBound(scribble) - 1
         scribble(i).draw()
         scribble(i).rMoveTo(100, 100)
         scribble(i).draw()
      Next

      ' call a rectangle specific function
      Dim rect As New Rectangle(0, 0, 15, 15)
      rect.setWidth(30)
      rect.draw()
   End Sub
End Module

Public Class Shape
   Private x
   Private y

   ' constructor
   Public Sub New(ByVal newx, ByVal newy)
      setX(newx)
      setY(newy)
   End Sub

   ' accessors for x & y coordinates
   Public Function getX()
      getX = x
   End Function
   Public Function getY()
      getY = y
   End Function
   Public Sub setX(ByVal newx)
      x = newx
   End Sub
   Public Sub setY(ByVal newy)
      y = newy
   End Sub

   ' move the x & y coordinates
   Public Sub moveTo(ByVal newx, ByVal newy)
      setX(newx)
      setY(newy)
   End Sub
   Public Sub rMoveTo(ByVal deltax, ByVal deltay)
      moveTo(deltax + getX(), deltay + getY())
   End Sub

   ' virtual routine - draw the shape
   Public Overridable Sub draw()
   End Sub
End Class

Public Class Rectangle : Inherits Shape
   Private width As Integer
   Private height As Integer

   ' constructor
   Public Sub New(ByVal newx, ByVal newy, ByVal newwidth, ByVal newheight)
      MyBase.New(newx, newy)
      setWidth(newwidth)
      setHeight(newheight)
   End Sub

   ' accessors for width & height
   Public Function getWidth()
      getWidth = width
   End Function
   Public Function getHeight()
      getHeight = height
   End Function
   Public Sub setWidth(ByVal newwidth)
      width = newwidth
   End Sub
   Public Sub setHeight(ByVal newheight)
      height = newheight
   End Sub

   ' draw the rectangle
   Public Overrides Sub draw()
      Console.WriteLine("Drawing a Rectangle at:({0},{1}), Width {2}, Height {3}", _
         getX(), getY(), getWidth(), getHeight())
   End Sub
End Class

Public Class Circle : Inherits Shape
   Private radius

   ' constructor
   Public Sub New(ByVal newx, ByVal newy, ByVal newradius)
      MyBase.New(newx, newy)
      setRadius(newradius)
   End Sub

   ' accessors for the radius
   Public Function getRadius()
      getRadius = radius
   End Function
   Public Sub setRadius(ByVal newradius)
      radius = newradius
   End Sub

   ' draw the circle
   Public Overrides Sub draw()
      Console.WriteLine("Drawing a Circle at:({0},{1}), Radius {2}", _
         getX(), getY(), getRadius())
   End Sub
End Class

Drawing a Rectangle at:(10,20), Width 5, Height 6
Drawing a Rectangle at:(110,120), Width 5, Height 6
Drawing a Circle at:(15,25), Radius 8
Drawing a Circle at:(115,125), Radius 8
Drawing a Rectangle at:(0,0), Width 30, Height 15