How to declare a dynamic array

[Linda]

How can I declare a two dimention array of character with dynamical
first dimention and static second dimention using mix of pointer* and
[]. I think "char *A[4]" means first dimention is static and second
dimension is dynamical. Thank you.

[Emmanuel Delahaye]

In 'comp.lang.c', ln******@yahoo.com (Linda) wrote:

How can I declare a two dimention array of character with dynamical
first dimention and static second dimention using mix of pointer* and
[]. I think "char *A[4]" means first dimention is static and second
dimension is dynamical. Thank you.

char (*A)[4] = malloc (sizeof *A * nb_of_elements);

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[Malcolm]

"Linda" <ln******@yahoo.com> wrote

How can I declare a two dimention array of character with dynamical
first dimention and static second dimention using mix of pointer* and
[]. I think "char *A[4]" means first dimention is static and second
dimension is dynamical. Thank you.

char *A[4];

is the same as

char* A[4];

which you will see is an array of 4 character pointers.

char (*A)[4] is what you want, but this syntax is horrible. 2d arrays in C,
beyond the very simplest declaration, are horrible.
What most programmers would do is declare

char *A;

and just manage the second dimension by hand. You see this quite commonly in
24 bit rgb images, for example.

[Christopher Benson-Manica]

Malcolm <ma*****@55bank.freeserve.co.uk> spoke thus:

char (*A)[4] is what you want, but this syntax is horrible. 2d arrays in C,
beyond the very simplest declaration, are horrible.
What most programmers would do is declare char *A;

Is the syntax really that bad? I would think your original
declaration would do a better job of conveying to an informed reader
that you have a dynamic array of 4 byte arrays...

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cyberspace.org | don't, I need to know. Flames welcome.

[Malcolm]

"Christopher Benson-Manica" <at***@nospam.cyberspace.org> wrote

Malcolm <ma*****@55bank.freeserve.co.uk> spoke thus:

char (*A)[4] is what you want, but this syntax is horrible. 2d arrays in
C, beyond the very simplest declaration, are horrible.
What most programmers would do is declare

char *A;

Is the syntax really that bad? I would think your original
declaration would do a better job of conveying to an informed reader
that you have a dynamic array of 4 byte arrays...

Yes it is. If you follow the ng you will see that there is a steady trickle
of newbies hopelessly confused by C's multi-dimensional arrays, largely
because most introductory textbooks introduce the 2d array at the same time
as the 1d array.
char (*A)[4] is gibberish. No-one should be expected to follow such a
construct, or use it in real code. Even the informed reader, who can work
out what it means, will find it hard to read and make mistakes.