C# | Gets or sets the value of the bit at a specific position in the BitArray

Last Updated : 11 Jul, 2025

BitArray.Item[Int32] Property is used to get or set the value of the bit at a specific position in the BitArray. Syntax:

public bool this[int index] { get; set; }

Here, the index is the zero-based Index of the value which is to get or set. Return Value: It returns a boolean value of the bit at position index. Exception: This property throws the ArgumentOutOfRangeException if the index is less than zero or index is equal to or greater than Count. Below programs illustrate the use of above-discussed property: Example 1:

CSharp

// C# program to illustrate the // BitArray.Item[Int32] Property using System; using System.Collections; class GFG {  // Driver code  public static void Main()  {  // Creating a BitArray myBitArr  BitArray myBitArr = new BitArray(5);  // Initializing all the bits in myBitArr  myBitArr[0] = false;  myBitArr[1] = true;  myBitArr[2] = true;  myBitArr[3] = false;  myBitArr[4] = true;  // Printing the values in myBitArr  Console.WriteLine("Initially the bits are as : ");  PrintIndexAndValues(myBitArr);  // after using item[int32] property  // changing the bit value of index 2  myBitArr[2] = false;  // Printing the values in myBitArr  Console.WriteLine("Finally the bits are as : ");  PrintIndexAndValues(myBitArr);  }  // Function to display bits  public static void PrintIndexAndValues(IEnumerable myArr)  {  foreach(Object obj in myArr)  {  Console.WriteLine(obj);  }  } }

Output:

 Initially the bits are as : False True True False True Finally the bits are as : False True False False True

Example 2:

CSharp

// C# program to illustrate the // BitArray.Item[Int32] Property using System; using System.Collections; class GFG {  // Driver code  public static void Main()  {  // Creating a BitArray myBitArr  BitArray myBitArr = new BitArray(5);  // Initializing all the bits in myBitArr  myBitArr[0] = true;  myBitArr[1] = false;  myBitArr[2] = false;  myBitArr[3] = false;  myBitArr[4] = true;  // after using item[int32] property  // it will give run time error as  // index is less than zero  myBitArr[-1] = false;  PrintIndexAndValues(myBitArr);  }  // Function to display bits  public static void PrintIndexAndValues(IEnumerable myArr)  {  foreach(Object obj in myArr)  {  Console.WriteLine(obj);  }  } }

Runtime Error:

Unhandled Exception: System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index

Note: Retrieving and setting the value of this property are an O(1) operation. Reference: