C# | Copying BitArray elements to an Array

The BitArray class manages a compact array of bit values, which are represented as Booleans, where true indicates that the bit is on i.e, 1 and false indicates the bit is off i.e, 0. This class is contained in System.Collections namespace.
BitArray.CopyTo(Array, Int32) method is used to copy the entire BitArray to a compatible one-dimensional Array, starting at the specified index of the target array.

Properties:

• The BitArray class is a collection class in which the capacity is always the same as the count.
• Elements are added to a BitArray by increasing the Length property.
• Elements are deleted by decreasing the Length property.
• Elements in this collection can be accessed using an integer index. Indexes in this collection are zero-based.

Syntax:

public void CopyTo (Array arr, int index);

Parameters:

• arr: It is the one-dimensional array which is the destination of the elements copied from BitArray. The Array must have zero-based indexing.
• index: It is the zero-based index in array at which copying begins.

Exceptions:

• ArgumentNullException : If the arr is null.
• ArgumentOutOfRangeException : If the index is less than zero.
• ArgumentException : If the arr is multidimensional OR the number of elements in the source BitArray is greater than the available space from index to the end of the destination array.
• InvalidCastException : If type of the source BitArray cannot be cast automatically to the type of the destination array.

Below given are some examples to understand the implementation in a better way:

Example 1:

// C# code to copy BitArray to Array,
// starting at the specified index
// of the target array
using System;
using System.Collections;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a BitArray
        BitArray myBitArr = new BitArray(4);

        myBitArr[0] = true;
        myBitArr[1] = true;
        myBitArr[2] = true;
        myBitArr[3] = true;

        // Creating a bool array
        bool[] myBoolArr = new bool[8];

        myBoolArr[0] = false;
        myBoolArr[1] = false;

        // Copying BitArray to Array,
        // starting at the specified index
        // of the target array
        myBitArr.CopyTo(myBoolArr, 3);

        // Displaying elements in myBoolArr
        foreach(Object obj in myBoolArr)
        {
            Console.WriteLine(obj);
        }
    }
}

Output:

False
False
False
True
True
True
True
False

Example 2:

// C# code to copy BitArray to Array,
// starting at the specified index
// of the target array
using System;
using System.Collections;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a BitArray
        BitArray myBitArr = new BitArray(3);

        myBitArr[0] = true;
        myBitArr[1] = true;
        myBitArr[2] = true;

        // Creating a bool array
        bool[] myBoolArr = new bool[8];

        myBoolArr[0] = false;
        myBoolArr[1] = false;
        myBoolArr[2] = false;

        // Copying BitArray to Array,
        // starting at the specified index
        // of the target array
        // This should raise "ArgumentOutOfRangeException"
        // as index is less than 0
        myBitArr.CopyTo(myBoolArr, -2);

        // Displaying elements in myBoolArr
        foreach(Object obj in myBoolArr)
        {
            Console.WriteLine(obj);
        }
    }
}

Runtime Error:

Unhandled Exception:
System.ArgumentOutOfRangeException: Non-negative number required.
Parameter name: index

Note:

• The specified array must be of a compatible type. Only bool, int, and byte types of arrays are supported.
• This method uses Array.Copy to copy the elements.
• This method is an O(n) operation, where n is Count.

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.bitarray.copyto?view=netframework-4.7.2