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Array.Sort Method (Array, Int32, Int32)

.NET Framework 1.1

Sorts the elements in a section of a one-dimensional Array using the IComparable interface implemented by each element of the Array.

[Visual Basic]
Overloads Public Shared Sub Sort( _
   ByVal array As Array, _
   ByVal index As Integer, _
   ByVal length As Integer _
)
[C#]
public static void Sort(
 Array array,
 int index,
 int length
);
[C++]
public: static void Sort(
 Array* array,
 int index,
 int length
);
[JScript]
public static function Sort(
   array : Array,
 index : int,
 length : int
);

Parameters

array
The one-dimensional Array to sort.
index
The starting index of the range to sort.
length
The number of elements in the range to sort.

Exceptions

Exception Type Condition
ArgumentNullException array is a null reference (Nothing in Visual Basic).
RankException array is multidimensional.
ArgumentOutOfRangeException index is less than the lower bound of array.

-or-

length is less than zero.

ArgumentException index and length do not specify a valid range in array.
InvalidOperationException One or more elements in array do not implement the IComparable interface.

Remarks

Each element within the specified section of array must implement the IComparable interface to be capable of comparisons with every other element in array.

If the sort is not successfully completed, the results are undefined.

This method uses the QuickSort algorithm. This is an O(n ^2) operation, where n is the number of elements to sort, with an average of θ(n log n).

This implementation performs an unstable sort; that is, if two elements are equal, their order might not be preserved. In contrast, a stable sort preserves the order of elements that are equal.

Example

[Visual Basic, C#, C++] The following code example shows how to sort the values in an Array using the default comparer and a custom comparer that reverses the sort order. Note that the result might vary depending on the current CultureInfo.

[Visual Basic] 
Imports System
Imports System.Collections

Public Class SamplesArray

   Public Class myReverserClass
      Implements IComparer

      ' Calls CaseInsensitiveComparer.Compare with the parameters reversed.
      Function Compare(x As Object, y As Object) As Integer _
         Implements IComparer.Compare
         Return New CaseInsensitiveComparer().Compare(y, x)
      End Function 'IComparer.Compare

   End Class 'myReverserClass

   Public Shared Sub Main()

      ' Creates and initializes a new Array and a new custom comparer.
      Dim myArr As [String]() =  {"The", "QUICK", "BROWN", "FOX", "jumps", "over", "the", "lazy", "dog"}
      Dim myComparer = New myReverserClass()

      ' Displays the values of the Array.
      Console.WriteLine("The Array initially contains the following values:")
      PrintIndexAndValues(myArr)

      ' Sorts a section of the Array using the default comparer.
      Array.Sort(myArr, 1, 3)
      Console.WriteLine("After sorting a section of the Array using the default comparer:")
      PrintIndexAndValues(myArr)

      ' Sorts a section of the Array using the reverse case-insensitive comparer.
      Array.Sort(myArr, 1, 3, myComparer)
      Console.WriteLine("After sorting a section of the Array using the reverse case-insensitive comparer:")
      PrintIndexAndValues(myArr)

      ' Sorts the entire Array using the default comparer.
      Array.Sort(myArr)
      Console.WriteLine("After sorting the entire Array using the default comparer:")
      PrintIndexAndValues(myArr)

      ' Sorts the entire Array using the reverse case-insensitive comparer.
      Array.Sort(myArr, myComparer)
      Console.WriteLine("After sorting the entire Array using the reverse case-insensitive comparer:")
      PrintIndexAndValues(myArr)

   End Sub 'Main

   Public Shared Sub PrintIndexAndValues(myArr() As [String])

      Dim i As Integer
      For i = 0 To myArr.Length - 1
         Console.WriteLine("   [{0}] : {1}", i, myArr(i))
      Next i
      Console.WriteLine()

   End Sub 'PrintIndexAndValues

End Class 'SamplesArray


'This code produces the following output.
'
'The Array initially contains the following values:
'   [0] : The
'   [1] : QUICK
'   [2] : BROWN
'   [3] : FOX
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'After sorting a section of the Array using the default comparer:
'   [0] : The
'   [1] : BROWN
'   [2] : FOX
'   [3] : QUICK
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'After sorting a section of the Array using the reverse case-insensitive comparer:
'   [0] : The
'   [1] : QUICK
'   [2] : FOX
'   [3] : BROWN
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'After sorting the entire Array using the default comparer:
'   [0] : BROWN
'   [1] : dog
'   [2] : FOX
'   [3] : jumps
'   [4] : lazy
'   [5] : over
'   [6] : QUICK
'   [7] : the
'   [8] : The
'
'After sorting the entire Array using the reverse case-insensitive comparer:
'   [0] : the
'   [1] : The
'   [2] : QUICK
'   [3] : over
'   [4] : lazy
'   [5] : jumps
'   [6] : FOX
'   [7] : dog
'   [8] : BROWN


[C#] 
using System;
using System.Collections;

public class SamplesArray  {
 
   public class myReverserClass : IComparer  {

      // Calls CaseInsensitiveComparer.Compare with the parameters reversed.
      int IComparer.Compare( Object x, Object y )  {
          return( (new CaseInsensitiveComparer()).Compare( y, x ) );
      }

   }

   public static void Main()  {
 
      // Creates and initializes a new Array and a new custom comparer.
      String[] myArr = { "The", "QUICK", "BROWN", "FOX", "jumps", "over", "the", "lazy", "dog" };
      IComparer myComparer = new myReverserClass();
 
      // Displays the values of the Array.
      Console.WriteLine( "The Array initially contains the following values:" );
      PrintIndexAndValues( myArr );
 
      // Sorts a section of the Array using the default comparer.
      Array.Sort( myArr, 1, 3 );
      Console.WriteLine( "After sorting a section of the Array using the default comparer:" );
      PrintIndexAndValues( myArr );

      // Sorts a section of the Array using the reverse case-insensitive comparer.
      Array.Sort( myArr, 1, 3, myComparer );
      Console.WriteLine( "After sorting a section of the Array using the reverse case-insensitive comparer:" );
      PrintIndexAndValues( myArr );

      // Sorts the entire Array using the default comparer.
      Array.Sort( myArr );
      Console.WriteLine( "After sorting the entire Array using the default comparer:" );
      PrintIndexAndValues( myArr );

      // Sorts the entire Array using the reverse case-insensitive comparer.
      Array.Sort( myArr, myComparer );
      Console.WriteLine( "After sorting the entire Array using the reverse case-insensitive comparer:" );
      PrintIndexAndValues( myArr );

   }
 
   public static void PrintIndexAndValues( String[] myArr )  {
      for ( int i = 0; i < myArr.Length; i++ )  {
         Console.WriteLine( "   [{0}] : {1}", i, myArr[i] );
      }
      Console.WriteLine();
   }
}


/* 
This code produces the following output.

The Array initially contains the following values:
   [0] : The
   [1] : QUICK
   [2] : BROWN
   [3] : FOX
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

After sorting a section of the Array using the default comparer:
   [0] : The
   [1] : BROWN
   [2] : FOX
   [3] : QUICK
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

After sorting a section of the Array using the reverse case-insensitive comparer:
   [0] : The
   [1] : QUICK
   [2] : FOX
   [3] : BROWN
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

After sorting the entire Array using the default comparer:
   [0] : BROWN
   [1] : dog
   [2] : FOX
   [3] : jumps
   [4] : lazy
   [5] : over
   [6] : QUICK
   [7] : the
   [8] : The

After sorting the entire Array using the reverse case-insensitive comparer:
   [0] : the
   [1] : The
   [2] : QUICK
   [3] : over
   [4] : lazy
   [5] : jumps
   [6] : FOX
   [7] : dog
   [8] : BROWN

*/


[C++] 
#using <mscorlib.dll>

using namespace System;
using namespace System::Collections;

public __gc class myReverserClass : public IComparer
{
   // Calls CaseInsensitiveComparer::Compare with the parameters reversed.
   int IComparer::Compare(Object* x, Object* y)
   {
      return((new CaseInsensitiveComparer())->Compare(y, x));
   }
};

void PrintIndexAndValues(String* myArr[])
{
   for (int i = 0; i < myArr->Length; i++) {
      Console::WriteLine(S"   [{0}] : {1}", __box(i), myArr[i]);
   }
   Console::WriteLine();
}

int main()
{
   // Creates and initializes a new Array and a new custom comparer.
   String* myArr[] = { S"The", S"QUICK", S"BROWN", S"FOX", S"jumps", S"over", S"the", S"lazy", S"dog" };
   IComparer* myComparer = new myReverserClass();

   // Displays the values of the Array.
   Console::WriteLine(S"The Array initially contains the following values:");
   PrintIndexAndValues(myArr);

   // Sorts a section of the Array using the default comparer.
   Array::Sort(myArr, 1, 3);
   Console::WriteLine(S"After sorting a section of the Array using the default comparer:");
   PrintIndexAndValues(myArr);

   // Sorts a section of the Array using the reverse case-insensitive comparer.
   Array::Sort(myArr, 1, 3, myComparer);
   Console::WriteLine(S"After sorting a section of the Array using the reverse case-insensitive comparer:");
   PrintIndexAndValues(myArr);

   // Sorts the entire Array using the default comparer.
   Array::Sort(myArr);
   Console::WriteLine(S"After sorting the entire Array using the default comparer:");
   PrintIndexAndValues(myArr);

   // Sorts the entire Array using the reverse case-insensitive comparer.
   Array::Sort(myArr, myComparer);
   Console::WriteLine(S"After sorting the entire Array using the reverse case-insensitive comparer:");
   PrintIndexAndValues(myArr);
}

/* 
This code produces the following output.

The Array initially contains the following values:
   [0] : The
   [1] : QUICK
   [2] : BROWN
   [3] : FOX
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

After sorting a section of the Array using the default comparer:
   [0] : The
   [1] : BROWN
   [2] : FOX
   [3] : QUICK
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

After sorting a section of the Array using the reverse case-insensitive comparer:
   [0] : The
   [1] : QUICK
   [2] : FOX
   [3] : BROWN
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

After sorting the entire Array using the default comparer:
   [0] : BROWN
   [1] : dog
   [2] : FOX
   [3] : jumps
   [4] : lazy
   [5] : over
   [6] : QUICK
   [7] : the
   [8] : The

After sorting the entire Array using the reverse case-insensitive comparer:
   [0] : the
   [1] : The
   [2] : QUICK
   [3] : over
   [4] : lazy
   [5] : jumps
   [6] : FOX
   [7] : dog
   [8] : BROWN

*/

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, Common Language Infrastructure (CLI) Standard

See Also

Array Class | Array Members | System Namespace | Array.Sort Overload List | IComparable | BinarySearch | Performing Culture-Insensitive String Operations in Arrays

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