From: Lutz <lutzmueller@...>
Date: 2005-04-24T09:49:32+09:00
Subject: Re: Integer/Float oddity


michael.b.masi@gmail.com wrote:
> Glenn Parker wrote:
> > horati0@linuxmail.org wrote:
> > > not really an oddity, more a lack of understanding on my part
> regarding
> > > ruby's internal type conversion...
> > >
> > > (100*(1.15-1))
> > > => 15.0
> > >
> > > (100*(1.15-1)).to_int
> > > => 14
> > >
> > > (100*(1.15-1)).to_int.round
> > > => 15
> >
> > FWIW, I get 14.  Perhaps you meant (100*(1.15-1)).round.to_int ?
> >
>
> oops, yep thats what i meant.  thanks for all the replies to my
query;
> i figured it had something to do with the internal representation of
fp
> numbers.
>
> this whole thing started as a conversation i was having with my dad
> about the relative merits of various programming languages.  he is a
> die-hard xbasic user, and pointed me to the following post on an xb
> list:
>
> ---------------------------------------------------------------------
>
> [snip]
>
> Message: 7
> Date: Wed, 30 Mar 2005 12:59:42 -0000
> From: "Bruno Schaefer" <bup.schaefer@...>
> Subject: XBasic is one of the best!
>
>
> I'm back now to work with XBasic, because there are strange things
> with other languages.
>
> If you try to calculate the following simple expression
>
> INT(100*(1.15-1))
>
> XBasic produces the correct result: 15.
>
> This is a calculation, which is solved by children easy.
>
> But try this with other languages
> (e.g. newLISP, Visual Basic, Liberty Basic, IBasic, Yabasic, Python)
> you will get the result
>
> 14 !!!!?
>
> What a nonsense ! Does somebody understand this ?
>
> This is one the reason for me to use XBasic!
>
> ---------------------------------------------------------------------
> i'm assuming that since this behaviour is exhibited in ruby and the
> rest of the above "other languages" and NOT xbasic that it is really
> due to an idiosyncracy of xbasic that the "right" answer comes out.
>
> so the question becomes, what is different about xbasic's internal
> numeric representation that allows it to give a correct answer to
this
> seemingly simple number manipulation?  
> 
> horati0