C# 0 The Complete Reference

The Bitwise AND, OR, XOR, and NOT Operators

The bitwise operators AND, OR, XOR, and NOT are 

&

,

|

,

^

, and 

~

. They perform the same 

operations as their Boolean logic equivalents described earlier. The difference is that the 

bitwise operators work on a bit-by-bit basis. The following table shows the outcome of each 

operation using 1s and 0s:

p

q

p & q

p | q

p ^ q

~p

0

0

0

0

0

1

1

0

0

1

1

0

0

1

0

1

1

1

1

1

1

1

0

0

In terms of its most common usage, you can think of the bitwise AND as a way to turn 

bits off. That is, any bit that is 0 in either operand will cause the corresponding bit in the 

outcome to be set to 0. For example

      1 1 0 1  0 0 1 1

&   1 0 1 0  1 0 1 0

      --------------------

      1 0 0 0  0 0 1 0

Operator

Result

&

Bitwise AND

|

Bitwise OR

^

Bitwise exclusive OR (XOR)

>>

Shift right

<<

Shift left

~

One’s complement (unar y NOT)

T

ABLE

 4-1 

The Bitwise Operators

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The following program demonstrates the 

&

 by using it to convert odd numbers into 

even numbers. It does this by turning off bit zero. For example, the low-order byte of the 

number 9 in binary is 0000 1001. When bit zero is turned off, this number becomes 8, 

or 0000 1000 in binary.

// Use bitwise AND to make a number even.

using System;

class MakeEven {

  static void Main() {

    ushort num;

    ushort i;

    for(i = 1; i <= 10; i++) {

      num = i;

      Console.WriteLine("num: " + num);

      num = (ushort) (num & 0xFFFE);

      Console.WriteLine("num after turning off bit zero: "

                        +  num + "\n");

    }

  }

}

The output from this program is shown here:

num: 1

num after turning off bit zero: 0

num: 2

num after turning off bit zero: 2

num: 3

num after turning off bit zero: 2

num: 4

num after turning off bit zero: 4

num: 5

num after turning off bit zero: 4

num: 6

num after turning off bit zero: 6

num: 7

num after turning off bit zero: 6

num: 8

num after turning off bit zero: 8

num: 9

num after turning off bit zero: 8

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