That's an ODD piece of code....

This clearly isn't the right way to do things, but it's really not that odd.

The author might have premonitions that $x/2 is converted to a floating point number. That ain't so bad a premonition, you know.

I have to admit I have done similar checks... when teaching myself BASIC in Grade 3 and 4 (elementary school.
Didn't know anything about modulus...

Definitely a WTF. Mosulus is how it's supposed to happen.

In other news, I'm leaving from Baltimore tonight to go to Philly by way of St. Louis.

;)

Nice site. I blogrolled ya!

Aaron

I have studied 4 books on PHP, the official PHP documentation, and countless other web sites for 5 years. I STILL don't know what ($x & 1) does.

I think the problem here is a lack of COMPREHENSIVE BEGINNER documentation on the subject. (And if you think that's bad, try finding something comprehensive for beginners concerning UNIX!)

& is a bitwise AND operator, meaning that for each bit of the values, AND-operation is made and value resulted from these operations is returned. In this case it's used to check if the value is even or not:
Binary representation of 1 (in 8 bits): 00000001
ANDing any (either) binary digit with 0 results 0, so ANDing with 00000001 results in 0, if the last bit of the compared number isn't 1, for example
2 in binary: 00000010
2 & 1:
00000010
00000001 &
----------
00000000

So ANDing a value with 1 returns zero if the value is even and non-zero if the value is odd.

I don't think this subject even should be covered in PHP's documentation as it has more to do with mathematics and low level data representation. For this reason I also suggest using the modulus operator insteads.

I use modulus a lot for coloring output to resemble greenbar paper (odd lines in a slightly different color for readabilty across wide columns). Also handy for making X by Y grids.

Acually, thats (almost) quite smart. You would want it to be more like?
if($x=2*( round($x/2) ) ) {
....
}
That means....
if(something=2*( round(half of something) ) ) {
....
}
Well if its even, rounding it after its been divided wont change anything. Then its timesed back up. So if its even, something=something

Now if its odd, one half of the odd number being rounded will make a difference. Then youll end up with something like 3=4, ect.

I once used that equation for spitting out odd numbers in a loop, then I found out about for() "steps". Uhg. :-D