strange rounding

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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Re: strange rounding by bart (Canon) on Nov 29, 2004 at 13:06 UTC
Oh no, not that FAQ again. Anyway, the best way to round to two decimals, is using sprintf: `$units = sprintf "%.2f", $units$p;` [download] In case you don't like trailing zeroes (maybe you do), as in "124.00", you can get rid of them using `$units =~ s/\.?0+$//;` [download] turning "123.50" into "123.5", and "124.00" into "124". Only* do this when you know your number contains a decimal point.	[reply] [d/l] [select]
Re^2: strange rounding by osunderdog (Deacon) on Nov 29, 2004 at 15:24 UTC
I have found Math::Round a great package for rounding. `$perl -MMath::Round -e "print nearest(0.01, 3.14159)" 3.14` [download] *"Look, Shiny Things!"* is not a better business strategy than compatibility and reuse. OSUnderdog	[reply] [d/l]
Re: strange rounding by reneeb (Chaplain) on Nov 29, 2004 at 13:06 UTC
in these nodes the same topic was discussed: Strange rounding Error in Perl, Bug? 1+1 != 2	[reply]
Re^2: strange rounding by Anonymous Monk on Nov 29, 2004 at 16:03 UTC
Well, I first unsuccessfuilly serached for int(), because I could not imagine that the division of 100 causes this, second I thought, that other must have been unpleased as well. Finally I want to let you know that even `$u = sprintf "%.2f", (int(0.5+($u$p100))/100);` [download] produces 123.99 and not 124.00. Only Math::Round had the correct answers. Carl	[reply] [d/l]
Re^3: strange rounding by BrowserUk (Patriarch) on Nov 29, 2004 at 16:07 UTC
Try this: `print int(0.500000000000001+($u$p100))/100;` [download] Examine what is said, not who speaks. "But you should never overestimate the ingenuity of the sceptics to come up with a counter-argument." -Myles Allen "Think for yourself!" - Abigail "Time is a poor substitute for thought"--theorbtwo "Efficiency is intelligent laziness." -David Dunham "Memory, processor, disk in that order on the hardware side. Algorithm, algorithm, algorithm on the code side." - tachyon	[reply] [d/l]
Re^4: strange rounding by Anonymous Monk on Nov 30, 2004 at 09:28 UTC
Re: strange rounding by edan (Curate) on Nov 29, 2004 at 12:56 UTC
`perldoc -q decimal` [download] -- edan	[reply] [d/l]
Re: strange rounding by I0 (Priest) on Dec 01, 2004 at 07:13 UTC
What are $units and $p when you do this? I only get 123.99 when int(0.5 + ($units$p100) ) == 12399	[reply]
Re: strange rounding by Anonymous Monk on Nov 29, 2004 at 12:39 UTC
btw, even `12400/10 => 1239.9 ?? and 124000.1 => 1239.9` [download] having stange results. But PLEASE don't tell me that I have to convert those numbers into strings and re-formate them (like): `s/(\d)(\d\d)/$1.$2/ or $price = substring(..).'.'.substr(..) (I asume that s/../../ is exactly doing this)` [download] Carl	[reply] [d/l] [select]