Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!amdcad!ames!hao!boulder!sunybcs!rutgers!dayton!umn-cs!herndon
From: herndon@umn-cs.UUCP (Robert Herndon)
Newsgroups: comp.lang.c
Subject: Re: Printing binary
Message-ID: <2488@umn-cs.UUCP>
Date: Tue, 27-Oct-87 17:21:46 EST
Article-I.D.: umn-cs.2488
Posted: Tue Oct 27 17:21:46 1987
Date-Received: Wed, 4-Nov-87 05:47:35 EST
References: <35@ateng.UUCP> <3194@sol.ARPA> <2783@xanth.UUCP> <235@snark.UUCP> <247@snark.UUCP>
Organization: University of Minnesota, Minneapolis
Lines: 55
Summary: A generic recursive, sprintf compatible int to ascii conversion routine.

In article <247@snark.UUCP>, eric@snark.UUCP (Eric S. Raymond) writes:
> In article <1646@spar.SPAR.SLB.COM>, hunt@spar.SPAR.SLB.COM (Neil Hunt) writes:
> > This is crying out for recursion: [followed by a print_binary implementation]
> 
> Now that's more elegant than my internal-to-hex-nybbles-to binary hack (which
> I posted mostly for its giggle value). It also avoids the flaw of the second
> proposal (which is nonportable, requiring this ugly #define in source for the
> machine's word length). 
> 
> But your trick can't be generalized to do the sprintf analogue. GONG!
This isn't exactly the ticket, but it shows how it can be done.
(This is a library routine I've used for years.)
-----------------------------------------------Cut Here.
#include <stdio.h>

/*
 * itoa(n, b, s)
 * Puts base b character representation of n into s, terminates
 * representation with null.  Returns pointer to null at end of
 * representation.
 *
 * Works for n >= 0, 2 <= b <= 32.
 * Robert Herndon, May 1977.
 */
char *itoa(n, b, s)
int n, b;
char *s;
{
	if(n/b != 0) {
		s = itoa(n/b, b, s);
	}
	*s++ = "0123456789ABCDEFGHIJKLMNOPQRSTUV"[n%b];
	*s = '\0';
	return s;
}

main(ac, av)
int ac;
char *av[];
{
	char result[50];

	if(ac < 3) {
		fprintf(stderr, "Usage: itoa <number> <base>");
		exit(1);
	}
	itoa(atoi(av[1]), atoi(av[2]), result);
	printf("%s(10) = %s(%s)\n", av[1], result, av[2]);
}

-- 
Robert Herndon				Dept. of Computer Science,
...!ihnp4!umn-cs!herndon		Univ. of Minnesota,
herndon@umn-cs.ARPA			136 Lind Hall, 207 Church St. SE
herndon.umn-cs@csnet-relay.ARPA		Minneapolis, MN  55455