Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!haven!adm!smoke!gwyn
From: gwyn@smoke.brl.mil (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: Summary:  Converting ascii hex to pure hex values
Message-ID: <14367@smoke.brl.mil>
Date: 7 Nov 90 09:19:09 GMT
References: <302@cti1.UUCP>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 20

In article <302@cti1.UUCP> mpledger@cti1.UUCP (Mark Pledger) writes:
>If you have a character string with the ascii representation of hex values
>(e.g. s[] = "63", which will be stored as TWO hex byte values \x9 & \x9.

No, the two successive values will be 0x36 and 0x33.

>I only want to store them as ONE hex byte of \x63.  ...  I am interested in
>creating (or finding) a routine that will take a character string as the
>argument, and returning the hex result in the same character string.

This is a trivial exercise.  WARNING: String literals (as opposed to
arrays of char) are not necessarily modifiable.

	void func( char *s ) {
		register int i = s[0] - '0' << 4 | s[1] - '0';
		s[0] = i;
		s[1] = '\0';
	}

This could be easily be made into a macro.