Check if two BitArray objects are equal in C#

Syntax

Following is the syntax for using the Equals() method −

bool result = bitArray1.Equals(bitArray2);

Reference Equality vs Content Equality

Using Reference Assignment

When you assign one BitArray to another, both variables reference the same object in memory −

using System;
using System.Collections;

public class Demo {
   public static void Main(){
      BitArray arr1 = new BitArray(2);
      BitArray arr2 = new BitArray(2);
      arr1[0] = false;
      arr1[1] = true;
      Console.WriteLine("Elements in BitArray1...");
      foreach (bool res in arr1){
         Console.WriteLine(res);
      }
      arr2[0] = false;
      arr2[1] = true;
      Console.WriteLine("Elements in BitArray2...");
      foreach (bool res in arr2){
         Console.WriteLine(res);
      }
      BitArray arr3 = new BitArray(2);
      arr3 = arr2;
      Console.WriteLine("Is BitArray2 equal to BitArray3? = "+arr2.Equals(arr3));
   }
}

The output of the above code is −

Elements in BitArray1...
False
True
Elements in BitArray2...
False
True
Is BitArray2 equal to BitArray3? = True

Using Content Comparison

When two BitArray objects are created separately, even with identical content, Equals() returns false −

using System;
using System.Collections;

public class Demo {
   public static void Main(){
      BitArray arr1 = new BitArray(2);
      BitArray arr2 = new BitArray(2);
      arr1[0] = false;
      arr1[1] = true;
      Console.WriteLine("Elements in BitArray1...");
      foreach (bool res in arr1){
         Console.WriteLine(res);
      }
      arr2[0] = false;
      arr2[1] = true;
      Console.WriteLine("Elements in BitArray2...");
      foreach (bool res in arr2){
         Console.WriteLine(res);
      }
      Console.WriteLine("Is BitArray1 equal to BitArray2? = "+arr1.Equals(arr2));
   }
}

The output of the above code is −

Elements in BitArray1...
False
True
Elements in BitArray2...
False
True
Is BitArray1 equal to BitArray2? = False

Custom Content-Based Equality Method

To perform true content comparison, you need to create a custom method −

using System;
using System.Collections;

public class Demo {
   public static bool AreBitArraysEqual(BitArray arr1, BitArray arr2) {
      if (arr1.Length != arr2.Length) return false;
      for (int i = 0; i 

The output of the above code is −

Reference equality: False
Content equality: True


Conclusion

The BitArray.Equals() method performs reference equality, not content comparison. For content-based equality, you need to implement a custom comparison method that checks each bit individually. Understanding this distinction is crucial when working with BitArray collections in C#.