syntax help: bits shifting?

raedbenz

hi,,

What does this mean?

$a << -$b

The minus sign is confusing me.
i found it within this condition :

return($b >= 0 ? $a >> $b : $a << -$b);

cheers

nrg_alpha

You can read up about bitwise operators here.

raedbenz

hi,,
that's fine for bitwise generally only. but what about the minus sign

$a << -$b

????
thanks

johanafm

?: operator works like this:
(condition) ? (do if condition is true) : (do if condition is false)

So, whenever $b is less than 0, that is, a negative number:
If $b = -1, then -$b = 1.

So the above translates to: shift left, when b is positive, or right, when b is negative, by the absolute value of $b.

raedbenz

johanafm;10926620 wrote:
?: operator works like this:
(condition) ? (do if condition is true) : (do if condition is false)

So, whenever $b is less than 0, that is, a negative number:
If $b = -1, then -$b = 1.

So the above translates to: shift left, when b is positive, or right, when b is negative, by the absolute value of $b.

i think it is the other way around.
"shift right, when b is positive, or left, when b is negative, by the absolute value of $b"

johanafm

You are correct.