IComparable.CompareTo Method

Parameters

• obj
  Type: System.Object
  An object to compare with this instance.

Return Value

Type: System.Int32
A 32-bit signed integer that indicates the relative order of the objects being compared. The return value has these meanings:

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

      If obj Is Nothing Then Return 1

      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 Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim temperatures(9) As Temperature
      ' 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(ctr - 1) = temp
      Next

      ' Sort Array.
      Array.Sort(temperatures)

      For Each temp As Temperature In temperatures
         outputBlock.Text &= temp.Fahrenheit & vbCrLf
      Next
   End Sub
End Module
' The example displays the following output (individual
' values may vary because they are randomly generated):
'       2
'       7
'       16
'       17
'       31
'       37
'       58
'       66
'       72
'       95

using System;
using System.Collections;

public class Temperature : IComparable
{
   // The temperature value
   protected double temperatureF;

   public int CompareTo(object obj)
   {
      if (obj == null) return 1;

      Temperature otherTemperature = obj as Temperature;
      if (otherTemperature != null)
         return this.temperatureF.CompareTo(otherTemperature.temperatureF);
      else
         throw new ArgumentException("Object is not a Temperature");
   }

   public double Fahrenheit
   {
      get
      {
         return this.temperatureF;
      }
      set
      {
         this.temperatureF = value;
      }
   }

   public double Celsius
   {
      get
      {
         return (this.temperatureF - 32) * (5.0 / 9);
      }
      set
      {
         this.temperatureF = (value * 9.0 / 5) + 32;
      }
   }
}

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      Temperature[] temperatures = new Temperature[10];
      // Initialize random number generator.
      Random rnd = new Random();

      // Generate 10 temperatures between 0 and 100 randomly.
      for (int ctr = 1; ctr <= 10; ctr++)
      {
         int degrees = rnd.Next(0, 100);
         Temperature temp = new Temperature();
         temp.Fahrenheit = degrees;
         temperatures[ctr - 1] = temp;
      }

      // Sort ArrayList.
      Array.Sort(temperatures);

      foreach (Temperature temp in temperatures)
         outputBlock.Text += temp.Fahrenheit + "\n";

   }
}
// The example displays the following output (individual
// values may vary because they are randomly generated):
//       2
//       7
//       16
//       17
//       31
//       37
//       58
//       66
//       72
//       95