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Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!ihnp4!ihuxe!foss
From: foss@ihuxe.UUCP (foss)
Newsgroups: net.lang.c
Subject: Re: C Style
Message-ID: <1217@ihuxe.UUCP>
Date: Fri, 13-Sep-85 09:16:32 EDT
Article-I.D.: ihuxe.1217
Posted: Fri Sep 13 09:16:32 1985
Date-Received: Sat, 14-Sep-85 06:24:47 EDT
References: <180@chinet.UUCP>
Organization: AT&T Bell Laboratories
Lines: 62

> 
> The question:
> 	Which of the following code segments is more understandable,
> 
> GOTO VERSION:
> 	. . .
> 	noecho();		/* turn off echo */
> retry:
> 	move(4,10);		/* set cursor position */
> 	refresh();		/* update screen */
> 	ch = getch();		/* get input character (without echo) */
> 	if ((ch < '1' || ch > '5') && ch != 'E')
> 	{			/* valid input is 1 thru 5 or 'E' */
> 		putchar(BELL);	/* sound bell on invalid input */
> 		goto retry;
> 	}
> 	addch(ch);		/* echo the valid character */
> 	refresh();		/* update screen */
> 	. . .
> 
> versus NO GOTO VERSION
> 
> 	for ( ; (((ch=getch()) < '1' || ch > '5') && ch != 'E') ; )
> 		putchar(BELL);
> 	addch(ch);
> 	refresh();
> 
----------------------------

Enable Flame Thrower:

It is a tie. Both versions are lame and don't use 
the most appropriate construct avaliable.  
	-> Goto's are for teen-agers who play video games 
	   (and grow up to play D & D). 
	-> With the 'for' loop, the general idea is:

	   for( initial condition; final condition; change condition )
		foo;

	   Unfortunately, the 'for' loop above has no 
	   initial condition and no change condition.
.............................

I suggest a more appropriate construct, the 'while' loop:

	while(( ch =  getch()) != EOF )
	{
		if(( ch < '1' || ch > '5') && ch != 'E')
			putchar( BELL );
		addch( ch );
		refresh();
	} /* end while */

This IS more readable and demonstrates what 
really needs to be done by the loop.

Disable Flame Thrower:

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Raymond M. Foss -> AT&T Bell Laboratories -> ..!ihnp4!ihuxe!foss
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