Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!ucsd!chem.ucsd.edu!tps
From: tps@chem.ucsd.edu (Tom Stockfisch)
Newsgroups: comp.lang.c
Subject: Re: Help needed to round-off a number
Message-ID: <478@chem.ucsd.EDU>
Date: 21 May 89 01:40:57 GMT
References: <2666@oregon.uoregon.edu>
Reply-To: tps@chem.ucsd.edu (Tom Stockfisch)
Organization: Chemistry Dept, UC San Diego
Lines: 22

In article <2666@oregon.uoregon.edu> michelbi@oregon.uoregon.edu (Michel Biedermann) writes:
>Is there a C function (user defined or primitive (?)) that will let me
>truncate or round-off a number UP TO a certain decimal place.  For example
>transforming .567 into .6 or -1.502 into -1.5.


If speed isn't crucial, use

double
round( x, sigfigs )
	double	x;
	int	sigfigs;
{
	char	buf[sizeof(double)*20];	/* nice conservative size */

	sprintf( buf, "%.*g", x, sigfigs );
	sscanf( buf, "%lf", &x );
	return	x;
}
-- 

|| Tom Stockfisch, UCSD Chemistry	tps@chem.ucsd.edu