From: Marnen Laibow-Koser <marnen@...>
Date: 2009-10-29T03:52:43+09:00
Subject: Re: Ruby can't subtract ?

Aldric Giacomoni wrote:
> Matthew K. Williams wrote:
>>> irb(main):016:0> 123.6 - 123.0
>>> => 0.599999999999994
>>>
>>> That's a little strange.. Isn't it?
>> 
>> No, it's not.  Welcome to the wonderfully confusing world of floating
>> point math...
> 
> Oh, thanks. Can I have some pop-corn and an introductory pamphlet before 
> I bash my head against the wall? :)

Most languages these days use IEEE 754-style floats, which leads to the 
imprecision you saw.

http://c2.com/cgi/wiki?IeeeSevenFiftyFour

Don't use floats for serious arithmetic.

Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen@marnen.org
-- 
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