From: "Sly" <sly AT aussie DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Floating Point???
Date: 5 Mar 1997 06:20:21 GMT
Organization: Sly
Lines: 34
Message-ID: <01bc292d$d7fed300$8a081ecb@sly>
References: <4b5_9703051119 AT softtech DOT brisnet DOT org DOT au> <5fin95$f8 AT news DOT ox DOT ac DOT uk>
NNTP-Posting-Host: max0ppp08.bne.aussie.net
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

George Foot <gfoot AT mc31 DOT merton DOT ox DOT ac DOT uk> wrote in article
<5fin95$f8 AT news DOT ox DOT ac DOT uk>...
> Ron T Lewis (ron DOT t DOT lewis AT softtech DOT brisnet DOT org DOT au) wrote:
> 
> : int main()
> : {
> : float a;
> : a=4.00/5.00;
> : printf("float = %.12f\n",a);
> : return(1);
> : }
> : Ans = 0.800000011921
> 
> : The correct answer should be 0.800000000000 but he gets these
extroneous 
> : numbers tacked on the end???
> 
> `float' numbers aren't that accurate; use `double's instead. Replace
`float'
> with `double' throughout, and change `%.12f' to `%.12lf', and you should
get
> the right answer.
> 
> -- 
> George Foot <gfoot AT mc31 DOT merton DOT ox DOT ac DOT uk>
> Merton College, Oxford.
> 

floats are only precise up to about 6 digits or so.  doubles are precise up
to .. err .. is it 10?

-- 
TTFN
Sly (Steve)