Date: Tue, 23 Oct 2007 17:18:00 -0500 From: Derek Ragona <derek@computinginnovations.com> To: Harald Schmalzbauer <h.schmalzbauer@omnisec.de>, freebsd-questions@freebsd.org Subject: Re: Mentor for C self study wanted Message-ID: <6.0.0.22.2.20071023171535.0244b420@mail.computinginnovations.com> In-Reply-To: <200710232324.09851.h.schmalzbauer@omnisec.de> References: <200710232044.53240.h.schmalzbauer@omnisec.de> <20071023220134.3abd635e@epia-2.farid-hajji.net> <20071023162454.93851854.wmoran@potentialtech.com> <200710232324.09851.h.schmalzbauer@omnisec.de>
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At 04:24 PM 10/23/2007, Harald Schmalzbauer wrote:
>Am Dienstag, 23. Oktober 2007 22:24:54 schrieb Bill Moran:
> > In response to cpghost <cpghost@cordula.ws>:
> > > On Tue, 23 Oct 2007 20:44:52 +0200
> > >
> > > Harald Schmalzbauer <h.schmalzbauer@omnisec.de> wrote:
> > > > The first one was for example the attached code: Why does it segfau=
lt?
> > >
> > > Mailman ate the attachment... Can't see it here.
> >
> > I may be out of line, but I think if you're using FreeBSD as your
> > learning platform, that it wouldn't be a problem to ask this list.
> >> Harald Schmalzbauer wrote:
> > > Am Dienstag, 23. Oktober 2007 21:43:52 schrieben Sie:
> > >>> Hello Aryeh,
> > >>>
> > >>> I'm willing to pay fair fees, but are you interested in "micro paym=
ent"
> > >>> ;) ?
> > >>
> > >> For other reasons I love micro payments.
> > >>
> > >>> Serious, I'll have the one or other short question per week (I'm
> > >>> usually busy, just making spare time lessons from my book (UTC-1 sp=
are
> > >>> time)).
> > >>
> > >> Just so I know what level to present on what is your background in CS
> > >> and programming?
> > >
> > > CS??
> > > I'm able to solve problems analytically, but I don't know any language
> > > really well.
> > > I know bourne shell, csh, pascal, and basic. And a tiny bit asm, but
> > > that's been on ZX81.
> >
> > Although, you'll have to include your code inline to get past the
> > sanitizers.
>
>Thanks all,
>
>here was my example, just for completeness, I found mentors for my needs.
>
>Thanks a lot to all!
>
>
>#include <stdio.h>
>
>void main()
>{
> short nnote;
>
> // Numerischen Notenwert einlesen
> printf("Bitte numerischen Schulnotenwert eingeben: ");
> scanf("%d",&nnote);
>
> switch (nnote)
> {
> case 1: printf("Die Note %d entspricht sehr gut.",nnote);
> break;
> case 2: printf("Die Note %d entspricht gut.",nnote);
> break;
> case 3: printf("Die Note %d entspricht befriedigend.",nnote);
> break;
> case 4: printf("Die Note %d entspricht ausreichend.",nnote);
> break;
> case 5: printf("Die Note %d entspricht mangelhaft.",nnote);
> break;
> case 6: printf("Die Note %d entspricht ungen=FCgend.",nnote);
> break;
> default: printf("%d ist keine zul=E4ssige Schulnote!");
> }
> printf("\n");
>}
>
>P.S.:
>I found that declaring nnote as int soleves my problem, but I couldn=C4t
>understand why.
>Another one was the result of default: nnote was -1077942208 instead of 9 =
for
>example.
if you check the man page on scanf:
d Matches an optionally signed decimal integer; the next pointer must
be a pointer to int.
You shouldn't try to put a short into an int. Always declare the correct=
=20
size for variables. Your segv is because scanf was trying to put an int=20
where it won't fit.
You will get the same result if you go off the end of an array.
-Derek
--=20
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