Thanks for the info -----Original Message----- From: tedd [mailto:tedd@xxxxxxxxxxxx] Sent: Monday, January 09, 2006 3:26 PM To: php-general@xxxxxxxxxxxxx; Mark Steudel Subject: Re: Floating numbers truncating to two digits without rounding >I am calculating things like tax and want to format them so they only >have 2 digits past the decimal point. I've been using sprintf but just >noticed that it tends to round up. I want the same functionlity without rounding. Mark: Rounding? You can try round(), such as: <?php echo round(3.4); // 3 echo round(3.5); // 4 echo round(3.6); // 4 echo round(3.6, 0); // 4 echo round(1.95583, 2); // 1.96 echo round(1241757, -3); // 1242000 echo round(5.045, 2); // 5.05 echo round(5.055, 2); // 5.06 ?> But, as you can see, this rounds up (not the best). You may want to consider that there is more than one way to round a number. For example, there is no completely accurate solution for rounding any real number. If you want absolute precision, then you must use absolute numbers to whatever precision they are. However, this may not be obtainable because of continuos numbers like pi. As such, you may be forced to round. There are several different algorithms for rounding, such as truncation, floor (rounding down), ceiling (round up), common, and statistical. None are perfect, but some are more prone to errors than others. The least prone to error is the statistical, please review: "Statisticians method of rounding": http://en.wikipedia.org/wiki/Rounding And, if you ignore rounding, please review: http://www.ima.umn.edu/~arnold/disasters/disasters.html http://catless.ncl.ac.uk/php/risks/search.php?query=rounding tedd -- ---------------------------------------------------------------------------- ---- http://sperling.com/ -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
