pointer to arrays as parameter

[Michael Birkmose]

The following creates a function "test" that takes a parameter that is
a pointer to a multi dimensional array.

typedef int int_arr[][3];

void test(int_arr *foo) {
printf("%d\n", (*foo)[1][2]);
}

int main() {
int a[2][3]= {1,2,3,4,5,6};
test(&a);
}

However, how do I specify this, if I don't want to use the typedef?

E.g what I would LIKE to do is:
void test(int[][3] *foo) {...}

However this produces a parse error. Is there any way to avoid typedefing?
--
Michael Birkmose - stud.polyt
Aalborg University - Department of Computer Science
Fredrik Bajers Vej 7, B1-215

[Arthur J. O'Dwyer]

On Tue, 11 May 2004, Michael Birkmose wrote:

The following creates a function "test" that takes a parameter that is
a pointer to a multi dimensional array.

typedef int int_arr[][3];

void test(int_arr *foo) {
printf("%d\n", (*foo)[1][2]);
}

However, how do I specify this, if I don't want to use the typedef?

This is Rule Number One of C: Declaration mimics use.
You wrote (*foo)[x][y] to use 'foo'; now write (*foo)[x][y] to
declare 'foo'. And since (*foo)[x][y] is an 'int', stick an
'int' in front so the compiler knows what type it is.

void test(int (*foo)[][3]) {
printf("%d\n", (*foo)[1][2]);
}

Simple, huh?

-Arthur

[Eric Sosman]

Michael Birkmose wrote:

The following creates a function "test" that takes a parameter that is
a pointer to a multi dimensional array.

typedef int int_arr[][3];

void test(int_arr *foo) {
printf("%d\n", (*foo)[1][2]);
}

int main() {
int a[2][3]= {1,2,3,4,5,6};
test(&a);
}

However, how do I specify this, if I don't want to use the typedef?

E.g what I would LIKE to do is:
void test(int[][3] *foo) {...}

However this produces a parse error. Is there any way to avoid typedefing?

void test(int (*foo)[][3]) { ... }

Are you sure this is what you want to do, though? The
extra level of indirection doesn't seem to be necessary, and
you could instead write

void test(int foo[][3]) { ... }

and

test(foo);

without the `&' operator.

--
Er*********@sun.com

[Ben Pfaff]

Michael Birkmose <bi******@cs.auc.dk> writes:

typedef int int_arr[][3];

void test(int_arr *foo) {
printf("%d\n", (*foo)[1][2]);
}

However, how do I specify this, if I don't want to use the typedef?

You should get a copy of the cdecl program. Example session:

blp@blp:~(0)$ cdecl
Type `help' or `?' for help
cdecl> declare pointer to array of array 3 of int
int (*var)[][3]
cdecl> quit
blp@blp:~(0)$
--
"The lusers I know are so clueless, that if they were dipped in clue
musk and dropped in the middle of pack of horny clues, on clue prom
night during clue happy hour, they still couldn't get a clue."
--Michael Girdwood, in the monastery

[Joe Wright]

Ben Pfaff wrote:

Michael Birkmose <bi******@cs.auc.dk> writes:

typedef int int_arr[][3];

void test(int_arr *foo) {
printf("%d\n", (*foo)[1][2]);
}

However, how do I specify this, if I don't want to use the typedef?

You should get a copy of the cdecl program. Example session:

blp@blp:~(0)$ cdecl
Type `help' or `?' for help
cdecl> declare pointer to array of array 3 of int
int (*var)[][3]
cdecl> quit
blp@blp:~(0)$

Ben, where can I find cdecl.c source? I have my own versions of decl
and undecl from K&R2 examples but not a complete program. Please.
--
Joe Wright mailto:jo********@comcast.net
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Ben Pfaff]

Joe Wright <jo********@comcast.net> writes:

Ben, where can I find cdecl.c source? I have my own versions of decl
and undecl from K&R2 examples but not a complete program. Please.

Google for cdecl, or for cdecl.tar.gz. I note that one of the
hits lists "Chris Torek" as submitter--in 1986.
--
"Give me a couple of years and a large research grant,
and I'll give you a receipt." --Richard Heathfield

[Chris Torek]

>Joe Wright <jo********@comcast.net> writes:

Ben, where can I find cdecl.c source? I have my own versions of decl
and undecl from K&R2 examples but not a complete program. Please.

In article <87************@blp.benpfaff.org>
Ben Pfaff <bl*@cs.stanford.edu> writes:Google for cdecl, or for cdecl.tar.gz. I note that one of the
hits lists "Chris Torek" as submitter--in 1986.

I will note here that I did not write it, but I did some minor work
on a version of it at some point, presumably shortly before submitting
it in 1986. :-)
--
In-Real-Life: Chris Torek, Wind River Systems
Salt Lake City, UT, USA (40°39.22'N, 111°50.29'W) [phone]
email: forget about it http://web.torek.net/torek/index.html
Reading email is like searching for food in the garbage, thanks to spammers.