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]

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);

 

[Malcolm]

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]

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...

 

[Malcolm]

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.