Re: Re: #41401 [Opn->Bgs]: Order of Operations error on divide by negative
| From: | Richard Quadling | Date: | Wed, 16 May 2007 14:25:59 +0000 |
| Subject: | Re: Re: #41401 [Opn->Bgs]: Order of Operations error on divide by negative | ||
| References: | 1 2 3 4 | Groups: | php.internals |
| Request: | Send a blank email to internals+get-29470@lists.php.net to get a copy of this message | ||
On 16/05/07, Brian Moon <brianm@dealnews.com> wrote:
Michael Wallner wrote: tony2001@php.net wrote:I'm in the UK and I was taught (over 35 years ago at least) about BODMAS Brackets Orders Division Multiplication Addition Subtraction. http://en.wikipedia.org/wiki/BODMASShould all these three examples give the same result? $ php -r 'var_dump(-1/2*5, 1/-2*5, 1/2*-5);' float(-2.5) float(-0.1) float(-2.5) According to my memory of Please My Dear Aunt Sally these should be: -1/2*5 = -.1 1/-2*5 = -.1 1/2*-5 = -.1 So, that is bad if PHP answers that way. Someone please correct me if my memory is wrong. Is there some rule that negative values should be done first before positive values?ID: 41401 Updated by: tony2001@php.net Reported By: drlippman at yahoo dot com -Status: Open +Status: Bogus Bug Type: Math relatedOperating System: Windows, LinuxPHP Version: 4.4.7New Comment: [2007-05-15 15:44:07] drlippman at yahoo dot com Description: ------------ Left-to-right order of operations does not appear to be honored when dividing by a negative Reproduce code: --------------- 1/-2*5 Expected result: ---------------- -2.5 Actual result: -------------- -.1
-- Brian Moon Senior Developer ------------------------------ http://dealnews.com/ It's good to be cheap =) -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php-- ----- Richard Quadling Zend Certified Engineer : http://zend.com/zce.php?c=ZEND002498&r=213474731 "Standing on the shoulders of some very clever giants!"