Path: utzoo!utgpu!water!watmath!uunet!lll-winken!gryphon!freuden
From: freuden@gryphon.CTS.COM (Ralph Freudenberger)
Newsgroups: unix-pc.general
Subject: bug in _doprnt
Keywords: sprintf,_doprnt,printf
Message-ID: <2788@gryphon.CTS.COM>
Date: 6 Mar 88 20:28:44 GMT
Organization: Trailing Edge Technology, Redondo Beach, Ca.
Lines: 34



I just discovered a bug with the _doprnt procedure responsible for
library functions such as printf, sprintf, etc.

It seems that there is an inconsistency in the way the unix-pc rounds
off floating point numbers through _doprnt.

If one runs the following rough program and give the following input:
	0.4750 

one will get 0.47 as output.

But when one gives 0.4650 as input one receives 0.47 as output.....

very peculiar.

			ralph f.
#######################################
main()
{
	char	buf[10];
	double	f, atof();

	while (1) {
		printf("\ntype> ");
		scanf("%s",buf);
		f = atof(buf);
		printf("f is %f\n",f);


		sprintf(buf,"%.2f",f);
		printf("\nafter <%s>\n",buf);
	}
}