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From: bks@alfa.berkeley.edu (Brad Sherman)
Newsgroups: comp.software-eng
Subject: "Program Proving"
Message-ID: <1990Mar17.063012.24979@agate.berkeley.edu>
Date: 17 Mar 90 06:30:12 GMT
References: <52044@microsoft.UUCP> <2480006@hpcuhc.HP.COM> <1423@oravax.UUCP> <1990Mar16.210324.398@agate.berkeley.edu> <534@fwi.uva.nl>
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Reply-To: bks@alfa.berkeley.edu (Brad Sherman)
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In article <534@fwi.uva.nl> freek@fwi.uva.nl (Freek Wiedijk) writes:
> [various correct criticisms] and
> ...your program is _much_ too long, ...
without mentioning that there is some justification for omitting the line:
	*s = '\0';

I still think that it would be interesting to see a proof so I'll
try once more:

/* ---------------------------------------------------------------------
 *      RXUTOS
 *      RadiX Unsigned TO String.
 *      Converts an unsigned integer into a string of digits in any
 *      base in the range {2, ..., 36}.  Digits needed in the range
 *      {10, ..., 35} are represented by the characters {A, B, ..., Z}.
 *
 *      This function returns a pointer to a static buffer which is
 *       on each call. On error (radix out of range), a NULL
 *      pointer is returned.
 *
 *      Author: Bradley K. Sherman (bks@alfa.berkeley.edu)
 *	With thanks to: Freek Wiedijk (freek@fwi.uva.nl)
 *      Copyright (C), The Regents of the University of California, 1990
 */
char *
rxutos( n, radix )
register unsigned int   n;
register unsigned int   radix;
{
        static char     buf[ ( 8 * sizeof(unsigned int) ) + 1 ];
        char            *s = ( 8 * sizeof(unsigned int) ) + buf;   
 
        if ( radix < 2  ||  radix > 36 ) 
           return( 0 );
 
        *s = '\0';
        do {
		--s;
                *s = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"[n % radix];
		n /= radix;
        } while ( n > 0 );
 
        return( s );
}
/* --------------------- End of file rxutos.c ---------------------  */