<< Operator in PHP

Question

I've been trying to get a code together that would deduce what alternatives have been check in a multi-choice exam, but using sums of powers of two.

I found the following code online, but I'm not sure HOW it works, especially the operator <<. I could not find this on Google or PHPDoc.

Thank you.

$aSums = array();
for ($iCount = 0; $iCount < 32; $iCount++)
{
    $iMask = 1 << $iCount;

    if (($iNumber & $iMask) != 0)
    $aSums[] = $iMask;
}
return $aSums;

score 0 · Answer 1 · answered Dec 15 '13 at 21:30

0

It's a bitwise shift left, that is, multiply by 2^N.

answered Dec 15 '13 at 21:30

dkellner

8,726
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score 0 · Answer 2 · answered Dec 15 '13 at 21:30

0

It's a bitwise operator Shift left. From PHP documentation:

Shift the bits of $a $b steps to the left (each step means "multiply by two")

answered Dec 15 '13 at 21:30

amatellanes

3,645
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<< Operator in PHP

2 Answers2