C# 0 The Complete Reference

PART II

C h a p t e r   2 4 :  

C o l l e c t i o n s ,   E n u m e r a t o r s ,   a n d   I t e r a t o r s    

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To the properties specified by the interfaces that it implements, 

BitArray

 adds 

Length

,

which is shown here:

public int Length { get; set; }

Length

 sets or obtains the number of bits in the collection. Thus, 

Length

 gives the same 

value as does the standard 

Count

 property, which is defined for all collections. However, 

Count

 is read-only, but 

Length

 is not. Thus, 

Length

 can be used to change the size of a 

BitArray

. If you shorten a 

BitArray

, bits are truncated from the high-order end. If you 

lengthen a 

BitArray

, false bits are added to the high-order end.

BitArray

 defines the following indexer:

public bool this[int 

idx

] { get; set; }

You can use this indexer to get or set the value of an element.

Here is an example that demonstrates 

BitArray

:

// Demonstrate BitArray.

using System;

using System.Collections;

class BADemo {

  public static void ShowBits(string rem,

                         BitArray bits) {

    Console.WriteLine(rem);

    for(int i=0; i < bits.Count; i++)

      Console.Write("{0, -6} ", bits[i]);

    Console.WriteLine("\n");

  }

  static void Main() {

    BitArray ba = new BitArray(8);

    byte[] b = { 67 };

    BitArray ba2 = new BitArray(b);

    ShowBits("Original contents of ba:", ba);

    ba = ba.Not();

    ShowBits("Contents of ba after Not:", ba);

    ShowBits("Contents of ba2:", ba2);

    BitArray ba3 = ba.Xor(ba2);

    ShowBits("Result of ba XOR ba2:", ba3);

  }

}

The output is shown here:

Original contents of ba:

False  False  False  False  False  False  False  False

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774

 

P a r t   I I :  

E x p l o r i n g   t h e   C #   L i b r a r y

Contents of ba after Not:

True   True   True   True   True   True   True   True

Contents of ba2:

True   True   False  False  False  False  True   False

Result of ba XOR ba2:

False  False  True   True   True   True   False  True