The php bitwise XOR operator ^ (caret) with integers

Question

Hi i was just wondering if someone can explain to me how the following php code evaluates to 5

 <?php
      $a = 12 ^ 9;
      echo $a;
 ?>

so I know the output will be 5, but can someone explain to me how this works?

... why its homework/duplicate... check [here](https://stackoverflow.com/q/2674920/8928024) and [here](https://stackoverflow.com/q/249423/8928024) and [here](https://stackoverflow.com/q/13875762/8928024). — ZF007, Mar 19 '18 at 10:38

Spoody · Answer 1 · 2018-03-18T21:07:59.943

The ^ operator as you say is bitwise, so it converts the integer to a binary value.

12 is 00001100 in binary.

9 is 00001001 in binary.

A:       00001100  12
          XOR(^)
B:       00001001   9
         ---------
Output:  00000101   5

It is simply 1 if only one of the inputs is 1, here is the truth table for XOR:

+---+---+--------+
| A | B | Output |
+---+---+--------+
| 0 | 0 | 0      |
+---+---+--------+
| 0 | 1 | 1      |
+---+---+--------+
| 1 | 0 | 1      |
+---+---+--------+
| 1 | 1 | 0      |
+---+---+--------+

score 1 · Accepted Answer · edited Mar 18 '18 at 21:02

1

As far as I understand the process, php converts the numbers into binary and performs an XOR operation on them.

12 -> 1100
9  -> 1001
1100 XOR 1001 = 0101 = 5.

edited Mar 18 '18 at 21:02

Wai Ha Lee

7,664
52
54
80

answered Mar 18 '18 at 20:58

Joel Smith

86
3
3

Thanks this helped me visualize the answer – Justin Allara Mar 18 '18 at 21:20

score 1 · Answer 3 · answered Mar 18 '18 at 21:02

1

12  = 1100
09  = 1001
Xor = 0101 = 5

Exclusive or means only 1 bit at the same position to be high.

answered Mar 18 '18 at 21:02

DigiLive

1,022
1
12
21

Thank you. This helped me visualize the answer – Justin Allara Mar 18 '18 at 21:20

The php bitwise XOR operator ^ (caret) with integers

3 Answers3