Inverting all bit values in BitArray in C#

The BitArray class in C# is a collection of Boolean values represented as bits (1's and 0's). It is part of the System.Collections namespace and provides efficient storage and manipulation of binary data. One common operation is inverting all bit values in a BitArray.

Syntax

Following are the common methods to invert all bits in a BitArray

// Using built-in Not() method
bitArray.Not();

// Using XOR with true
bits[i] ^= true;

// Using Set() method with negation
bits.Set(i, !bits[i]);

Using the Built-in Not() Method

The simplest way to invert all bits in a BitArray is to use the built-in Not() method, which performs bitwise NOT operation on all elements

using System;
using System.Collections;

class Program {
   static void Main(string[] args) {
      // Create a BitArray with initial values
      BitArray bits = new BitArray(new[] { true, false, true, false });
      
      Console.WriteLine("Original BitArray:");
      PrintBits(bits);
      
      // Invert all bits using Not() method
      bits.Not();
      
      Console.WriteLine("After inversion:");
      PrintBits(bits);
   }
   
   static void PrintBits(BitArray bits) {
      for (int i = 0; i < bits.Count; i++) {
         Console.Write(bits[i] ? "1" : "0");
      }
      Console.WriteLine();
   }
}

The output of the above code is

Original BitArray:
1010
After inversion:
0101

Using XOR Operation

You can manually invert each bit using the XOR operator (^) with true. This approach gives you more control over the inversion process

using System;
using System.Collections;

class Program {
   static void Main(string[] args) {
      // Create a BitArray with some initial values
      BitArray bits = new BitArray(new[] { true, false, true, false });
      
      Console.WriteLine("Original BitArray:");
      PrintBits(bits);
      
      // Invert all bits using XOR with true
      for (int i = 0; i < bits.Length; i++) {
         bits[i] ^= true;
      }
      
      Console.WriteLine("After inversion:");
      PrintBits(bits);
   }
   
   static void PrintBits(BitArray bits) {
      for (int i = 0; i < bits.Count; i++) {
         Console.Write(bits[i] ? "1" : "0");
      }
      Console.WriteLine();
   }
}

The output of the above code is

Original BitArray:
1010
After inversion:
0101

Using Set() Method with Negation

Another approach is to use the Set() method combined with the logical NOT operator (!) to invert each bit individually

using System;
using System.Collections;

class Program {
   static void Main(string[] args) {
      int size = 8;
      BitArray bits = new BitArray(size);
      
      // Initialize with alternating pattern
      for (int i = 0; i < size; i++) {
         bits[i] = (i % 2 == 0);
      }
      
      Console.WriteLine("Before inversion:");
      PrintBits(bits);
      
      InvertBits(bits);
      
      Console.WriteLine("After inversion:");
      PrintBits(bits);
   }
   
   static void InvertBits(BitArray bits) {
      for (int i = 0; i < bits.Count; i++) {
         bits.Set(i, !bits[i]);
      }
   }
   
   static void PrintBits(BitArray bits) {
      for (int i = 0; i < bits.Count; i++) {
         Console.Write(bits[i] ? "1" : "0");
      }
      Console.WriteLine();
   }
}

The output of the above code is

Before inversion:
10101010
After inversion:
01010101

Performance Comparison

Conclusion

Inverting all bit values in a BitArray can be accomplished using three main approaches: the built-in Not() method (fastest), XOR operations for custom control, or the Set() method for explicit bit manipulation. The Not() method is recommended for simple inversions due to its efficiency and simplicity.