# PHP - Bitwise XOR and assignment operator

The Bitwise XOR and assignment operator (^=) assigns the first operand a value equal to the result of Bitwise XOR operation of two operands.

(x ^= y) is equivalent to (x = x ^ y)

The Bitwise XOR operator (^) is a binary operator which takes two bit patterns of equal length and performs the logical exclusive OR operation on each pair of corresponding bits. It returns 1 if only one of the bits is 1, else returns 0.

Bit_1Bit_2Bit_1 ^ Bit_2
000
101
011
110

The example below describes how bitwise XOR operator works:

```50 ^ 25 returns 43

50    ->    110010  (In Binary)
^ 25    ->  ^ 011001  (In Binary)
----        --------
43    <-    101011  (In Binary)
```

The code of using Bitwise XOR and assignment operator (^=) is given below:

```<?php
\$x = 50;
\$y = 25;

//Bitwise XOR and assignment operation
\$x ^= \$y;

//Displaying the result
echo "x = \$x";
?>
```

The output of the above code will be:

```x = 43
```

### Example: Swap two numbers without using temporary variable

The bitwise XOR and assignment operator can be used to swap the value of two variables. Consider the example below.

```<?php
function swap(\$x, \$y) {
echo "Before Swap.\n";
echo "x = \$x \n";
echo "y = \$y \n";

//Swap technique
\$x ^= \$y;
\$y ^= \$x;
\$x ^= \$y;

echo "After Swap.\n";
echo "x = \$x \n";
echo "y = \$y \n";
}

swap(10, 25);
?>
```

The above code will give the following output:

```Before Swap.
x = 10
y = 25
After Swap.
x = 25
y = 10
```

❮ PHP - Operators

5