From: "trans.  (T. Onoma)" <transami@...>
Date: 2004-10-28T06:06:37+09:00
Subject: Re: Rounding error, (100.0 * 9.95).to_i == 994

On Wednesday 27 October 2004 04:57 pm, Jamis Buck wrote:
| trans. (T. Onoma) wrote:
| > On Wednesday 27 October 2004 04:36 pm, Hal Fulton wrote:
| > | Jason DiCioccio wrote:
| > | > I'm confused now..  100.0 * 9.95 is clearly 995.  So what exactly is
| > | > the issue with floating point numbers is making this come out to
| > | > 994.999999999983 (or wahtever ;))?  If every language is plagued by
| > | > this problem, then I'd be curious to know the history behind it..
| > | >
| > | :) It's not history, it's math.
| > |
| > | Here's the short explanation.
| > |
| > | Remember repeating decimals, which you learned about in elementary
| > | school? For example, 1/3 = 0.33333... can't be expressed in a finite
| > | number of digits.
| >
| > Not exactly, '1/3' is finite.
|
| ... That's not what I learned in school. How many decimal digits does it
| take to express 1/3, then?

One, if you put a line over it --that's my point, any rational can be 
represented in a finite amount of space.

T.