I don't buy "zero doesn't count". But again, this is getting into serious math. It should be good enough to say 0-4 = 0, 5-9 = 10, but if you don't keep strict high precision throughout the whole process and round at every step, things are going to be off no matter what. It's just a matter of being off as little as possible (especially when it comes to money.. people are a little touchy about that). Don't malign zero though.. :) See also: Zero: The Biography of a Dangerous Idea (Paperback) by Charles Seife -TG = = = Original message = = = I wasn't aware of the accounting trick before today, but I believe I can explain it: If your numbers are statistically random, then the above solution will lead to an even distribution of rounding up and rounding down. The reason is simple: 0: No rounding. It's already there. (8.0 doesn't need to be rounded to 8 - it already *is* 8.) 1-4: You round down -> 4 of 9 times you round down. 5-9: You round up -> 5 of 9 times you round up. So you round up 11.1% more often than you round down. As a result, if you round up when it's odd, and down when it's even, you eliminate the 11.1% difference in when you'd round up then round down. That said, if someone were aware of the above rounding trick, it wouldn't take someone very much effort to come up with things like "fee structures" or "pricing structures" that could take advantage of that scheme to force rounding errors to remain permanently in the person's favor. I certainly hope that PHP continues to use the standard technique, and not the "accounting trick" above. :-) jon ___________________________________________________________ Sent by ePrompter, the premier email notification software. Free download at http://www.ePrompter.com. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
