Path: utzoo!utgpu!watmath!clyde!att!rutgers!mailrus!ames!haven!vrdxhq!daitc!jkrueger@daitc.daitc.mil
From: jkrueger@daitc.daitc.mil (Jonathan Krueger)
Newsgroups: comp.databases
Subject: Re: Style (was: C-DATABASE B-PLUS a quick look)
Summary: defensive programming: slow down and live
Keywords: style correctness
Message-ID: <262@daitc.daitc.mil>
Date: 17 Dec 88 08:01:38 GMT
References: <179@lakesys.UUCP> <2404@xyzzy.UUCP>
Sender: jkrueger@daitc.daitc.mil
Reply-To: jkrueger@daitc.daitc.mil (Jonathan Krueger)
Followup-To: comp.databases
Organization: Defense Applied Information Technology Center
Lines: 45
In-reply-to: throopw@xyzzy.UUCP (Wayne A. Throop)

In article <2404@xyzzy.UUCP>, throopw@xyzzy (Wayne A. Throop) writes:
>Applying all of these, we get the "improved" fragment (using prototypes):
>
>    #include <ctype.h>
>    char *strupr( char *s ) {
>        register char *p;
>        for( p=s; *p != '\0'; p+=1 )
>            *p = toupper( *p );
>        return( s );
>    }

Try strupr("Foo Bar"); on ASCII machines it returns "&OO".  The
correct code is:

    #include <ctype.h>
    char *strupr(s) char *s; {
        register char *p;
        for ( p=s; *p != '\0'; p+=1 )
            *p = islower(*p) ? toupper(*p) : *p;
        return( s );
    }

As a matter of style, I prefer my version (shown to perform opposite
operation):

#include	<ctype.h>
/* DLOWER: destructively lower-cases its arg, returns pointer to it */
char	*
dlower(str)
char	*str;
{
	char	*ptr = str;
	while (*ptr) {
		*ptr = isupper(*ptr) ? tolower(*ptr) : *ptr;
		ptr++;
	}
	return str;
}

References to reasons for my preferences: Plum-Hall Style Sheet, K&R.

-- Jon
-- 
Jonathan Krueger  ...uunet!daitc!jkrueger  jkrueger@daitc.arpa  (703) 998-4777
		My opinions are not necessarily those of my wallpaper.