If i have a pointer, char *. That i have checked is only 1 character long, is just casting it to a char using (char) the best way or is there another way ?
13  6732 
Matthew Jakeman <ma************ @yahoo.co.uk> scribbled the following: If i have a pointer, char *. That i have checked is only 1 character long, is just casting it to a char using (char) the best way or is there another way ?
Casting it to (char) is definitely the *WRONG* way. Use the * operator
for what it is meant for.
char *p;
/* ... */
char c;
c = *p;
--
/-- Joona Palaste (pa*****@cc.hel sinki.fi) ---------------------------\
| Kingpriest of "The Flying Lemon Tree" G++ FR FW+ M- #108 D+ ADA N+++|
| http://www.helsinki.fi/~palaste W++ B OP+ |
\----------------------------------------- Finland rules! ------------/
"You can pick your friends, you can pick your nose, but you can't pick your
relatives."
- MAD Magazine
On Mon, 28 Jul 2003 12:18:06 -0700
"Mike Wahler" <mk******@mkwah ler.net> wrote: Matthew Jakeman <ma************ @yahoo.co.uk> wrote in message
news:2003073021 0038.2ba49ef8.m a************@y ahoo.co.uk... If i have a pointer, char *.
Note that an object of type 'char*' (pointer to char),
is neither a character nor a string. It can represent
the address of an indivudual character (type 'char')
object. It cannot represent a character or a string.
That i have checked is only 1 character long,
It's very unlikely (but not impossible) that a pointer
on your system is only one character in size. And
again, note that this type can only contain an *address*
of a memory location, not a character value.
is just casting it to a char using (char)
Casting a char* to a char gives undefined (or is it
implementation-defined?) behavior.
the best way or is there another way ?
Best way to do what?
If you have a pointer of type 'char*' which contains the
address of a character object, or the address of the first
of an array of characters, you access the 'pointed to'
character with the dereference operator:
char some_stuff[] = "Hello";
char *p;
char c;
p = &some_stuff[1];
c = *p; /* The object 'c' now contains the character 'e' */
What C book(s) are you reading that don't explain
pointers?
-Mike
At what point in my message did i say i had been reading a C book / books that explain pointers ? I didn't, i asked for help, thanks for the paragraphs that have managed to make a simple question, from someone who is obviously dwarfed by your mass of intelligence, turn into something immensely more complex but the reply before yours was a lot less demeaning and a hell of a lot more helpful.
Matthew Jakeman <ma************ @yahoo.co.uk> wrote in message
news:2003073021 2931.42e9d2a1.m a************@y ahoo.co.uk... On Mon, 28 Jul 2003 12:18:06 -0700
"Mike Wahler" <mk******@mkwah ler.net> wrote:
Matthew Jakeman <ma************ @yahoo.co.uk> wrote in message
news:2003073021 0038.2ba49ef8.m a************@y ahoo.co.uk... If i have a pointer, char *.
Note that an object of type 'char*' (pointer to char),
is neither a character nor a string. It can represent
the address of an indivudual character (type 'char')
object. It cannot represent a character or a string.
That i have checked is only 1 character long,
It's very unlikely (but not impossible) that a pointer
on your system is only one character in size. And
again, note that this type can only contain an *address*
of a memory location, not a character value.
is just casting it to a char using (char)
Casting a char* to a char gives undefined (or is it
implementation-defined?) behavior.
the best way or is there another way ?
Best way to do what?
If you have a pointer of type 'char*' which contains the
address of a character object, or the address of the first
of an array of characters, you access the 'pointed to'
character with the dereference operator:
char some_stuff[] = "Hello";
char *p;
char c;
p = &some_stuff[1];
c = *p; /* The object 'c' now contains the character 'e' */
What C book(s) are you reading that don't explain
pointers?
-Mike
At what point in my message did i say i had been reading a C book / books
that explain pointers ?
You didn't. But imo you're only wasting your time
trying to learn C without textbooks. You can't learn
it 'piecemeal' by posting questions to usenet.
I didn't, i asked for help,
Help given here is intended to supplement, not replace,
the more traditional learning materials, such as books.
thanks for the paragraphs that have managed to make a simple question,
Your question wasn't only 'simple', but it was quite vague,
and indicated misconceptions, which I attempted to rectify.
from someone who is obviously dwarfed by your mass of intelligence,
Obnoxious sarcasm won't get you very far here.
turn into something immensely more complex
I don't think any of my explanation of a simple topic
was complex at all. If you find it so, then you really
do need some books.
but the reply before yours was a lot less demeaning
Please point out where in my reply I used any
'demeaning' text. All I did was state facts.
If you're upset with those facts, take it up
with them.
and a hell of a lot more helpful.
It might be, it might not. Joona had to guess at
what you really wanted. He also apparently chose
to overlook the parts of your post that indicate
your misconceptions about C.
-Mike
"Matthew Jakeman" <ma************ @yahoo.co.uk> wrote in message
news:2003073022 1954.41c59531.m a************@y ahoo.co.uk... On Mon, 28 Jul 2003 13:00:29 -0700
"Mike Wahler" <mk******@mkwah ler.net> wrote:
<snip>
At what point in my message did i say i had been reading a C book /
books that explain pointers ?
You didn't. But imo you're only wasting your time
trying to learn C without textbooks. You can't learn
it 'piecemeal' by posting questions to usenet.
At what point in my last reply did i say i hadn't been using books ? See
being a pedantic bastard who makes wrong assumptions can be annoying to some
people.. I didn't, i asked for help,
Help given here is intended to supplement, not replace,
the more traditional learning materials, such as books.
AGAIN, i never said i hadn't been using books, u assumed that i believe.
Huh? But you just said you weren't using books. Now I'm just confused.
--
Andy Zhang
On Wed, 30 Jul 2003 22:19:54 +0100, Matthew Jakeman wrote: On Mon, 28 Jul 2003 13:00:29 -0700
"Mike Wahler" <mk******@mkwah ler.net> wrote:
Matthew Jakeman <ma************ @yahoo.co.uk> wrote in message
news:2003073021 2931.42e9d2a1.m a************@y ahoo.co.uk... > On Mon, 28 Jul 2003 12:18:06 -0700
> "Mike Wahler" <mk******@mkwah ler.net> wrote:
>
> > Matthew Jakeman <ma************ @yahoo.co.uk> wrote in message
> > news:2003073021 0038.2ba49ef8.m a************@y ahoo.co.uk...
> > > If i have a pointer, char *.
> >
> > Note that an object of type 'char*' (pointer to char), is neither a
> > character nor a string. It can represent the address of an
> > indivudual character (type 'char') object. It cannot represent a
> > character or a string.
> >
> >
> > > That i have checked is only 1 character long,
> >
> > It's very unlikely (but not impossible) that a pointer on your
> > system is only one character in size. And again, note that this
> > type can only contain an *address* of a memory location, not a
> > character value.
> >
> >
> > >is just casting it to a char using (char)
> >
> > Casting a char* to a char gives undefined (or is it
> > implementation-defined?) behavior.
> >
> > > the best way or is there another way ?
> >
> > Best way to do what?
> >
> > If you have a pointer of type 'char*' which contains the address of
> > a character object, or the address of the first of an array of
> > characters, you access the 'pointed to' character with the
> > dereference operator:
> >
> > char some_stuff[] = "Hello";
> > char *p;
> > char c;
> >
> > p = &some_stuff[1];
> > c = *p; /* The object 'c' now contains the character 'e' */
> >
> > What C book(s) are you reading that don't explain pointers?
> >
> > -Mike
> >
> >
> > >
> >
> >
> At what point in my message did i say i had been reading a C book /
> books
that explain pointers ?
You didn't. But imo you're only wasting your time trying to learn C
without textbooks. You can't learn it 'piecemeal' by posting questions
to usenet.
At what point in my last reply did i say i hadn't been using books ? See
being a pedantic bastard who makes wrong assumptions can be annoying to
some people..
Any C book should explain pointers. If it dosen't, get a new one.
--
Freenet distribution not available
Having a wonderful wine, wish you were beer.
On Wed, 30 Jul 2003, Andy Zhang wrote:
"Matthew Jakeman" <ma************ @yahoo.co.uk> wrote in message "Mike Wahler" <mk******@mkwah ler.net> wrote:
>
> At what point in my message did i say i had been reading a C book /
> books that explain pointers ?
You didn't. But imo you're only wasting your time
trying to learn C without textbooks. You can't learn
it 'piecemeal' by posting questions to usenet.
At what point in my last reply did i say i hadn't been using books ? See
being a pedantic bastard who makes wrong assumptions can be annoying
to some people..
Help given here is intended to supplement, not replace,
the more traditional learning materials, such as books.
AGAIN, i never said i hadn't been using books, u assumed that i believe.
Huh? But you just said you weren't using books. Now I'm just confused.
Gee, haven't you ever read GEB? Just because the Tortoise says his
shell is green, and also that his shell is not green, you take a
perverse fascination in trying to make him admit a contradiction,
viz., that his shell is both green and not green! No wonder he's
annoyed!
;-)
-Arthur
"Matthew Jakeman" <ma************ @yahoo.co.uk> wrote in message
news:E3******** **********@news fep1-win.server.ntli .net...
<snip>
First of all Mike has been helping people on this newsgroup (with solid
answers) since I can remember(throug h all my different "handle" names that
I've used to post here), and from what I've seen in the past he meant
nothing "demeaning" by his reply. Many people take offense when their lack
of experience gets a light shined on it, including me sometimes. If you
noticed, he did not "flame" back.
The fact that he replied with more information than you had probably liked
is a good thing, as it is something you can learn by, rather than a single
answer that does not explain why what you are trying to do is invalid (from
char* to char). When posting on here please don't take informative replies
for granted.
"Joona I Palaste" <pa*****@cc.hel sinki.fi> wrote in message
news:bg******** **@oravannahka. helsinki.fi... Matthew Jakeman <ma************ @yahoo.co.uk> scribbled the following: If i have a pointer, char *. That i have checked is only 1 character
long, is just casting it to a char using (char) the best way or is there
another way ?
Casting it to (char) is definitely the *WRONG* way. Use the * operator
for what it is meant for.
char *p;
/* ... */
char c;
c = *p;
--
/-- Joona Palaste (pa*****@cc.hel sinki.fi) ---------------------------\
| Kingpriest of "The Flying Lemon Tree" G++ FR FW+ M- #108 D+ ADA N+++|
| http://www.helsinki.fi/~palaste W++ B OP+ |
\----------------------------------------- Finland rules! ------------/
"You can pick your friends, you can pick your nose, but you can't pick
your relatives."
- MAD Magazine
If you just want the first character (or if you are sure the pointer only
poits to onw char) then you can simply use:
char *p;
// ...
printf("%c\n",p[0]); // or whatever you want to with the char
Allan
Matthew Jakeman wrote: At what point in my last reply did i say i hadn't been using books ?
At what point did you decide that the way to get a newsgroup to help you
out was to act like a horse's ass? You're the one that doesn't
understand basic concepts, Mike (who's a good guy) took a lot time to
explain a good deal of relevant information to you. Instead of saying
thanks, you behave like a petulant child.
I suggest you get a major attitude adjustment immediately. Apologizing
would be a great start. Otherwise you'll end up in the collective bozo
files of the knowledgable group members, then you post your requests to
no one.
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