working of << operator??

<?php
$a = 1;
$b = 3;
//$c = 4;
//$d = 8;
//$e = 1.0;
//$f = $c + $d * 2;
//$g = $f % 20;
//$h = $b - $a + $c + 2;
//$i = $h << $c;
//$j = $i * $e;
//print $j;

echo $a << $b;
?>

PHP:

can anyone tell me the function of << operator

thanks

 

Shift the bits of $a $b steps to the left (each step means "multiply by two")
so 1*2 + 3*2 = 2+6

 

I'm not sure what mathmatical formula you are using there but this makes more sense to me:
$a * 2^$b = 1 * 2^3 = 1 * 8 = 8

This function is really only used if you care about the binary representation of your number in this case $a is 1 and $a << $b = 1000

It's usually used in combination with bitwise & and | for setting flags and hash functions and stuff in cases where you want to conserve memory.

 

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