What's the position of pointers

[Yee.Chuang]

When I began to learn C, My teacher told me that pointer is the most
difficult part of C, it makes me afraid of it. After finishing C
program class, I found that all the code I wrote in C contains little
pointers, obviously I avoid using them.
A few days ago when I was reading a book about programming, I was told
that pointers are the very essence of C language, if I couldn't use it
well, I'm a bad programmer, it's a big shock.
So now I'm wondering: what's the exact position of pointers in C? Is
it really necessary to learn how it works again?

[Cromulent]

On 2008-09-11 13:02:27 +0100, "Yee.Chuang " <mc*******@gmai l.comsaid:

When I began to learn C, My teacher told me that pointer is the most
difficult part of C, it makes me afraid of it. After finishing C
program class, I found that all the code I wrote in C contains little
pointers, obviously I avoid using them.
A few days ago when I was reading a book about programming, I was told
that pointers are the very essence of C language, if I couldn't use it
well, I'm a bad programmer, it's a big shock.
So now I'm wondering: what's the exact position of pointers in C? Is
it really necessary to learn how it works again?

Essential.

The standard library makes heavy use of them, as do most APIs. Also
things like passing arrays to functions decay into a pointer and so on
and so forth. Passing structs between functions, dynamic memory
allocation. The list is endless.

If you don't use pointers in C why don't you use a language like Python
instead?
--
"I disapprove of what you say, but I'll defend to the death your right
to say it." - Voltaire

[pete]

Yee.Chuang wrote:

When I began to learn C, My teacher told me that pointer is the most
difficult part of C, it makes me afraid of it. After finishing C
program class, I found that all the code I wrote in C contains little
pointers, obviously I avoid using them.
A few days ago when I was reading a book about programming, I was told
that pointers are the very essence of C language, if I couldn't use it
well, I'm a bad programmer, it's a big shock.
So now I'm wondering: what's the exact position of pointers in C? Is
it really necessary to learn how it works again?

Half of learning C, is learning to write functions.
Half of learning C, is learning to use pointers.
The other Half of learning C, is learning everything else about C.

Does that add up right? ;)

Most of the standard library functions,
take pointers as arguments,
so there is some importance to learning pointers well.

I mostly use pointers at every given opportunity.

You are most likely using subexpressions
which are being converted to pointer types,
without you being aware of it,
whenever you write code that you think avoids the use of pointers.

--
pete

[Richard Heathfield]

Yee.Chuang said:

When I began to learn C, My teacher told me that pointer is the most
difficult part of C,

He probably told you that not because they're hard to learn (they aren't!),
but because they're hard to teach!

it makes me afraid of it.

Yes, you're not alone. But it's worth overcoming that fear, because
pointers are the very essence of the C language. And once you "get" them,
your eyes will light up, and the word "POWER!" will pop into your head,
and there'll be no stopping you.

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

[Stephen Sprunk]

Yee.Chuang wrote:

When I began to learn C, My teacher told me that pointer is the most
difficult part of C, it makes me afraid of it. After finishing C
program class, I found that all the code I wrote in C contains little
pointers, obviously I avoid using them.

That's pretty much what happened with me; I came from a Pascal
background where I had used pointers once or twice in several years, and
before that BASIC, which didn't even have the concept at all.

What's funny is that, when I finally forced myself to learn, pointers
turned out to be a lot easier to deal with than I expected. There just
aren't many good books that teach it right, nor teachers who really
understand it well enough to explain it well to students.

A few days ago when I was reading a book about programming, I was told
that pointers are the very essence of C language, if I couldn't use it
well, I'm a bad programmer, it's a big shock.

I have to agree with that.

So now I'm wondering: what's the exact position of pointers in C? Is
it really necessary to learn how it works again?

You really can't unlock the power that C offers without understanding
and using pointers. If you don't, you're really just writing Pascal
that looks like C.

S

[CBFalconer]

Stephen Sprunk wrote:

Yee.Chuang wrote:

>When I began to learn C, My teacher told me that pointer is the
most difficult part of C, it makes me afraid of it. After
finishing C program class, I found that all the code I wrote in
C contains little pointers, obviously I avoid using them.

That's pretty much what happened with me; I came from a Pascal
background where I had used pointers once or twice in several
years, and before that BASIC, which didn't even have the concept
at all.

Then you weren't using Pascal thoroughly. The prime uses of
pointers are very similar between Pascal and C, but Pascal doesn't
allow the loose generic conversion of VAR parameters to pointers,
and similar things for arrays, etc. This allows Pascal to check
for most common errors, unlike C.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home .att.net>
Try the download section.

[August Karlstrom]

Yee.Chuang wrote:

When I began to learn C, My teacher told me that pointer is the most
difficult part of C, it makes me afraid of it. After finishing C
program class, I found that all the code I wrote in C contains little
pointers, obviously I avoid using them.
A few days ago when I was reading a book about programming, I was told
that pointers are the very essence of C language, if I couldn't use it
well, I'm a bad programmer, it's a big shock.
So now I'm wondering: what's the exact position of pointers in C? Is
it really necessary to learn how it works again?

In general you need pointers to build dynamic data structures like
linked lists. In C you also need pointers to simulate call by reference.
August

[Nick Keighley]

On 11 Sep, 22:28, CBFalconer <cbfalco...@yah oo.comwrote:

Stephen Sprunk wrote:

Yee.Chuang wrote:

When I began to learn C, My teacher told me that pointer is the
most difficult part of C, it makes me afraid of it. *After
finishing C program class, I found that all the code I wrote in
C contains little pointers, obviously I avoid using them.

That's pretty much what happened with me; I came from a Pascal
background where I had used pointers once or twice in several
years, and before that BASIC, which didn't even have the concept
at all.

Then you weren't using Pascal thoroughly. *The prime uses of
pointers are very similar between Pascal and C, but Pascal doesn't
allow the loose generic conversion of VAR parameters to pointers,
and similar things for arrays, etc. *This allows Pascal to check
for most common errors, unlike C.

yes I moved from pascal to C and didn't find pointers a problem.
They seemed very like pascal pointers. Though I thought the sysntax
was *very* strange!

On the other hand I'd programmed in Coral, Assmebler and had
brief exposure to BCPL. So pointers seemed quite normal!
--
Nick Keighley

Unicode is an international standard character set that can be used
to write documents in almost any language you're likely to speak,
learn or encounter in your lifetime, barring alien abduction.
(XML in a Nutshell)

[Yee.Chuang]

On Sep 12, 5:03*pm, Nick Keighley <nick_keighley_ nos...@hotmail. com>
wrote:

On 11 Sep, 22:28, CBFalconer <cbfalco...@yah oo.comwrote:

Stephen Sprunk wrote:

Yee.Chuang wrote:
>When I began to learn C, My teacher told me that pointer is the
>most difficult part of C, it makes me afraid of it. *After
>finishing C program class, I found that all the code I wrote in
>C contains little pointers, obviously I avoid using them.

That's pretty much what happened with me; I came from a Pascal
background where I had used pointers once or twice in several
years, and before that BASIC, which didn't even have the concept
at all.

Then you weren't using Pascal thoroughly. *The prime uses of
pointers are very similar between Pascal and C, but Pascal doesn't
allow the loose generic conversion of VAR parameters to pointers,
and similar things for arrays, etc. *This allows Pascal to check
for most common errors, unlike C.

yes I moved from pascal to C and didn't find pointers a problem.
They seemed very like pascal pointers. Though I thought the sysntax
was *very* strange!

On the other hand I'd programmed in Coral, Assmebler and had
brief exposure to BCPL. So pointers seemed quite normal!

--
Nick Keighley

Unicode is an international standard character set that can be used
to write documents in almost any language you're likely to speak,
learn or encounter in your lifetime, barring alien abduction.
* * * * * * *(XML in a Nutshell)

Something I forgot to tell: C is the first language I've learned,
after that I understand the basic skills of programming. Most of the
time I just use software like SAS, Matlab and R to solve problems.
Yes, I don't write any software, I just use them.
If learning pointers can help me with programing thoughts or improve
my program skills, I'm glad to do so.

[vippstar]

On Sep 12, 12:20 pm, "Yee.Chuang " <mcdrag...@gmai l.comwrote:

On Sep 12, 5:03 pm, Nick Keighley <nick_keighley_ nos...@hotmail. com>
wrote:

On 11 Sep, 22:28, CBFalconer <cbfalco...@yah oo.comwrote:

yes I moved from pascal to C and didn't find pointers a problem.
They seemed very like pascal pointers. Though I thought the sysntax
was *very* strange!

On the other hand I'd programmed in Coral, Assmebler and had
brief exposure to BCPL. So pointers seemed quite normal!

Something I forgot to tell: C is the first language I've learned,
after that I understand the basic skills of programming. Most of the
time I just use software like SAS, Matlab and R to solve problems.
Yes, I don't write any software, I just use them.
If learning pointers can help me with programing thoughts or improve
my program skills, I'm glad to do so.

Pointers are not a unique concept in C.
A pointer points to something. You can access that something via the
pointer.
That's all there is to it, as a generic concept.

Now, if you want to learn C pointers, first you'd have to understand
C's type system.
Given that p is char [4][2], you should immediately be able to tell
which type *p is, p[0][0], &p[0].
(answer: char [2], char, char (*)[2])

That's half the work. The other half is to read the semantics of
pointers.

HTH.