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The Bitwise NOT operator (~) is an unary operator which takes a bit pattern and performs the logical NOT operation on each bit. It is used to invert all of the bits of the operand. It is interesting to note that for any integer x, ~x is the same as -(x + 1).

Bit~ Bit
01
10

The below example describes how bitwise NOT operator works:


  528 -> 00000000000000000000001000010000 (in binary)
        ----------------------------------
 -529 <- 11111111111111111111110111101111 (in binary) 


The code of using Bitwise NOT operator (~) is given below:

<?php
$x = 528;

//Bitwise NOT operation
$z = ~$x;

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

The output of the above code will be:

x = 528
z = -529

❮ PHP - Operators