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From: jik@athena.mit.edu (Jonathan I. Kamens)
Newsgroups: misc.misc,comp.misc
Subject: Re: The "evil" GOTO (Was: 25 Years of BASIC)
Message-ID: <11346@bloom-beacon.MIT.EDU>
Date: 11 May 89 19:33:59 GMT
References: <1791@ubu.warwick.UUCP> <1436@onion.reading.ac.uk> <1814@ubu.warwick.UUCP> <1860@ubu.warwick.UUCP>
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Reply-To: jik@athena.mit.edu (Jonathan I. Kamens)
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In article <1860@ubu.warwick.UUCP> geoff@cs.warwick.ac.uk (Geoff
Rimmer) writes:

>Here is my solution.  Which does the same as that of the original
>poster, and in addition:
>
>(a) it checks the buffer overflowing;
>(b) it checks for EOF
>(c) it is correct C code

Actually, it is not correct C code for six reasons.  In fact, it
won't even compile.  It's not very intelligent in an argument like
this to be all high-and-mighty and post a code fragment that you
claim is "correct C code" when it won't even compile.

Here's the code you posted:

>#include <stdio.h>
>
>main()
>{
>	char str[4];
>	printf("Enter your sex: ");
>	do
>	{
>		fflush(stdin);
>		if (!fgets(str,3,stdin)) exit(1);
>	} while (*str!="m" && *str!="f") ? printf("m or f only: "):0);
>	printf("sex is %c\n",*str);
>}

1. You aren't flushing stdout after printing the prompt, and the
   prompt does not end in a newline, so in many operating systems the
   prompt will not be printed.
2. You flush stdin, but, to quote from the man page:
     Fflush causes any buffered data for the named output stream
     to be written to that file.  The stream remains open.
   In other words, fflush is not defined for input files, and stdin is
   input-only.
3. You assume that printf will return a non-zero value.  Now, I don't
   know about your implementation of printf, but mine (BSD 4.3)
   doesn't spec what printf returns, and I don't think that most
   implementations ahve such a specification (although I believe that
   ANSI says printf should return the number of characters it's
   printed).  In fact, I just compiled your program (with the two bugs
   below fixed, since it won't compile otherwise), and our IBM RT
   library seems to return 0 after a successful printf, so your code
   loses.
4. You're missing a parenthesis at the beginning of your while boolean
   expression.
5. You're comparing the value of a char to the value of a string
   pointer in your boolean expression.  It should be
     (*str!='m' && *str!='f')
   rather than what you have.
6. It doesn't print an error message if the fgets fails.  Now,
   granted, this isn't really "incorrect C," but rather "incorrect
   programming," but it should be pointed out nevertheless.

Oh, and one more thing: what the hell good is a program that does
nothing but get somebody's sex and print it? :-)

Jonathan Kamens			              USnail:
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