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Reverse Method (Array, Int32, Int32)
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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
)

Parameters

array
Type: System.Array

The one-dimensional Array to reverse.

index
Type: System.Int32

The starting index of the section to reverse.

length
Type: System.Int32

The number of elements in the section to reverse.

ExceptionCondition
ArgumentNullException

array is null.

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.

The Reverse method can be used to reverse a jagged array.

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
*/

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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