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Mail Archives: djgpp/2003/07/19/23:52:46

From: "A. Sinan Unur" <asu1 AT c-o-r-n-e-l-l DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Doubles won't see double!!
Date: 20 Jul 2003 03:14:13 GMT
Organization: Cornell University
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

"Noel O'Donnell" <nodger AT eircom DOT net> wrote in
news:KrkSa.23882$pK2 DOT 37447 AT news DOT indigo DOT ie: 

> Hello all,
> 
> Just wondering this:
> How can I perform maths on doubles, so that the result uses the full
> potential of a double's decimal spaces?
> 
> confused? ok, perhaps an example:
> 
> double x,y,z;
> x=22;
> y=7;
> z=x/y;
> cout<<z;
> 
> This will generally output something like:
> 3.1425(or whatever)
> however if I do the same sum on the windoze calculator:

ITYM division:

> 3.142857142957142857...................................you get the
> picture 
> 
> so my question is this: How can I make MY doubles behave like this?

Your doubles are behaving fine.

> is there a library that i need to include? any suggestions?

You need to set the appropriate options for cout.

#include <iomanip>
#include <iostream>

int main(void) {
	double x = 22;
	double y = 7;
	
	std::cout << std::setprecision(12) << x/y << std::endl;
}

Sinan.
-- 
A. Sinan Unur
asu1 AT c-o-r-n-e-l-l DOT edu
Remove dashes for address
Spam bait: mailto:uce AT ftc DOT gov

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