VB.Net/Class/Member Function

Define and use Member Function

Imports System
Public Class MainClass
    Shared Sub Main(ByVal args As String())
      Dim circle As Circle
      circle = New Circle(37, 43, 2.5) " instantiate Circle
      Console.WriteLine( "X coordinate is " & circle.X & vbCrLf & _
         "Y coordinate is " & circle.Y & vbCrLf & "Radius is " & _
         circle.Radius )
      circle.X = 2
      circle.Y = 2
      circle.Radius = 4.25
      Console.WriteLine("The new location and radius of circle are " & _
         vbCrLf & circle.ToString() )
      Console.WriteLine( "Diameter is " & _
         String.Format("{0:F}", circle.Diameter()) )
      Console.WriteLine("Circumference is " & _
         String.Format("{0:F}", circle.Circumference()) )
      Console.WriteLine( "Area is " & String.Format("{0:F}", circle.Area()) )
    End Sub
End Class
Public Class Circle
   " coordinate of center of Circle
   Private mX, mY As Integer
   Private mRadius As Double " Circle"s radius
   " default constructor
   Public Sub New()
      " implicit call to Object constructor occurs here
      X = 0
      Y = 0
      Radius = 0
   End Sub " New
   " constructor
   Public Sub New(ByVal xValue As Integer, _
      ByVal yValue As Integer, ByVal radiusValue As Double)
      " implicit call to Object constructor occurs here
      X = xValue
      Y = yValue
      Radius = radiusValue
   End Sub " New
   " property X
   Public Property X() As Integer
      Get
         Return mX
      End Get
      Set(ByVal xValue As Integer)
         mX = xValue " no need for validation
      End Set
   End Property " X
   " property Y 
   Public Property Y() As Integer
      Get
         Return mY
      End Get
      Set(ByVal yValue As Integer)
         mY = yValue " no need for validation
      End Set
   End Property " Y
   " property Radius
   Public Property Radius() As Double
      Get
         Return mRadius
      End Get
      Set(ByVal radiusValue As Double)
         If radiusValue > 0 Then
            mRadius = radiusValue
         End If
      End Set
   End Property " Radius
   " calculate Circle diameter
   Public Function Diameter() As Double
      Return mRadius * 2
   End Function " Diameter
   " calculate Circle circumference
   Public Function Circumference() As Double
      Return Math.PI * Diameter()
   End Function " Circumference
   " calculate Circle area
   Public Function Area() As Double
      Return Math.PI * mRadius ^ 2
   End Function " Area
   " return String representation of Circle 
   Public Overrides Function ToString() As String
      Return "Center = " & "[" & mX & ", " & mY & "]" & _
         "; Radius = " & mRadius
   End Function " ToString
End Class " Circle