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Array.Reverse Method (Array, Int32, Int32)

Reverses the sequence of the elements in a range of elements in the one-dimensional Array.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

public static void Reverse (
	Array array,
	int index,
	int length
)
public static void Reverse (
	Array array, 
	int index, 
	int length
)
public static function Reverse (
	array : Array, 
	index : int, 
	length : int
)
Not applicable.

Parameters

array

The one-dimensional Array to reverse.

index

The starting index of the section to reverse.

length

The number of elements in the section to reverse.

Exception typeCondition

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.

After a call to this method, the element at myArray[i], where i is any index in the array, moves to myArray[j], where j equals (myArray.Length + myArray.GetLowerBound(0)) - (i - myArray.GetLowerBound(0)) - 1.

This method is an O(n) operation, where n is length.

The following code example shows how to reverse the sort of the values in a range of elements in an Array.

using System;
public class SamplesArray  {

   public static void Main()  {

      // Creates and initializes a new Array.
      Array myArray=Array.CreateInstance( typeof(String), 9 );
      myArray.SetValue( "The", 0 );
      myArray.SetValue( "QUICK", 1 );
      myArray.SetValue( "BROWN", 2 );
      myArray.SetValue( "FOX", 3 );
      myArray.SetValue( "jumps", 4 );
      myArray.SetValue( "over", 5 );
      myArray.SetValue( "the", 6 );
      myArray.SetValue( "lazy", 7 );
      myArray.SetValue( "dog", 8 );

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

      // Reverses the sort of the values of the Array.
      Array.Reverse( myArray, 1, 3 );

      // Displays the values of the Array.
      Console.WriteLine( "After reversing:" );
      PrintIndexAndValues( myArray );
   }


   public static void PrintIndexAndValues( Array myArray )  {
      for ( int i = myArray.GetLowerBound(0); i <= myArray.GetUpperBound(0); i++ )
         Console.WriteLine( "\t[{0}]:\t{1}", i, myArray.GetValue( i ) );
   }
}
/* 
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 reversing:
    [0]:    The
    [1]:    FOX
    [2]:    BROWN
    [3]:    QUICK
    [4]:    jumps
    [5]:    over
    [6]:    the
    [7]:    lazy
    [8]:    dog
*/ 

import System.*;

public class SamplesArray
{
    public static void main(String[] args)
    {
        // Creates and initializes a new Array.
        Array myArray = Array.CreateInstance(String.class.ToType(), 9);
        myArray.SetValue("The", 0);
        myArray.SetValue("QUICK", 1);
        myArray.SetValue("BROWN", 2);
        myArray.SetValue("FOX", 3);
        myArray.SetValue("jumps", 4);
        myArray.SetValue("over", 5);
        myArray.SetValue("the", 6);
        myArray.SetValue("lazy", 7);
        myArray.SetValue("dog", 8);
        // Displays the values of the Array.
        Console.WriteLine("The Array initially contains the following values:");
        PrintIndexAndValues(myArray);
        // Reverses the sort of the values of the Array.
        Array.Reverse(myArray, 1, 3);
        // Displays the values of the Array.
        Console.WriteLine("After reversing:");
        PrintIndexAndValues(myArray);
    } //main

    public static void PrintIndexAndValues(Array myArray)
    {
        for (int i = myArray.GetLowerBound(0); i <= myArray.
            GetUpperBound(0); i++) {
            Console.WriteLine("\t[{0}]:\t{1}", (Int32)i, myArray.GetValue(i));
        }
    } //PrintIndexAndValues
} //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 reversing:
     [0]:    The
     [1]:    FOX
     [2]:    BROWN
     [3]:    QUICK
     [4]:    jumps
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog
 */

import System;

// Creates and initializes a new Array.
var myArray : System.Array= System.Array.CreateInstance( System.String, 9 );
myArray.SetValue( "The", 0 );
myArray.SetValue( "QUICK", 1 );
myArray.SetValue( "BROWN", 2 );
myArray.SetValue( "FOX", 3 );
myArray.SetValue( "jumped", 4 );
myArray.SetValue( "over", 5 );
myArray.SetValue( "the", 6 );
myArray.SetValue( "lazy", 7 );
myArray.SetValue( "dog", 8 );

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

// Reverses the sort of the values of the Array.
System.Array.Reverse( myArray, 1, 3 );

// Displays the values of the Array.
Console.WriteLine( "After reversing:" );
PrintIndexAndValues( myArray );
 
 
function PrintIndexAndValues( myArray : System.Array )  {
   for ( var i : int = myArray.GetLowerBound(0); i <= myArray.GetUpperBound(0); i++ )
      Console.WriteLine( "\t[{0}]:\t{1}", i, myArray.GetValue( i ) );
}
 /* 
 This code produces the following output.
 
 The Array initially contains the following values:
     [0]:    The
     [1]:    QUICK
     [2]:    BROWN
     [3]:    FOX
     [4]:    jumped
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog
 After reversing:
     [0]:    The
     [1]:    FOX
     [2]:    BROWN
     [3]:    QUICK
     [4]:    jumped
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog
 */ 

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0

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