[.net]IComparable Interface

Sorting Example

Imports System.Collections


Public Class Temperature
  Implements IComparable
  ' The temperature value
  Protected temperatureF As Double

  Public Overloads Function CompareTo(ByVal obj As Object) As Integer _
      Implements IComparable.CompareTo

      Dim otherTemperature As Temperature = TryCast(obj, Temperature)
      If otherTemperature IsNot Nothing Then
          Return Me.temperatureF.CompareTo(otherTemperature.temperatureF)
      Else
         Throw New ArgumentException("Object is not a Temperature")
      End If 
  End Function

  Public Property Fahrenheit() As Double
      Get
          Return temperatureF
      End Get
      Set(ByVal Value As Double)
          Me.temperatureF = Value
      End Set
  End Property

  Public Property Celsius() As Double
      Get
          Return (temperatureF - 32) * (5/9)
      End Get
      Set(ByVal Value As Double)
          Me.temperatureF = (Value * 9/5) + 32
      End Set
  End Property
End Class

Public Module CompareTemperatures
 Public Sub Main()
    Dim temperatures As New ArrayList
    ' Initialize random number generator.
    Dim rnd As New Random()

    ' Generate 10 temperatures between 0 and 100 randomly.
    For ctr As Integer = 1 To 10
       Dim degrees As Integer = rnd.Next(0, 100)
       Dim temp As New Temperature
       temp.Fahrenheit = degrees
       temperatures.Add(temp) 
    Next

    ' Sort ArrayList.
    temperatures.Sort()

    For Each temp As Temperature In temperatures
       Console.WriteLine(temp.Fahrenheit)
    Next    
 End Sub
End Modul

IComparable Interface