Dynamically loop through array of structures

[uidzer0]

Hey everyone,

I apologize in advance for this novice question however I'm not having
any luck finding the answer myself.

I'm attempting to loop through an array of structures passed to a
function, however I'm not sure how to obtain the number of elements in
the array.

The structure is defined as:
typedef struct {
time_t creation_date;
int priority;
char *text;
} note;

And here's the function prototype:
void get_notes(note *notes);

How would I dynamically loop through *notes?

[Richard Bos]

uidzer0 <be************@gmail.comwrote:

I'm attempting to loop through an array of structures passed to a
function, however I'm not sure how to obtain the number of elements in
the array.

You can't. You have to pass that number in to the function, use a
terminator element, or have some other way to find out. This is the same
for all arrays, whether or not they're made of structs.

Richard

[uidzer0]

On Apr 15, 9:13*am, [e-mail] (Richard Bos) wrote:

uidzer0 <[e-mail]:

I'm attempting to loop through an array of structures passed to a
function, however I'm not sure how to obtain the number of elements in
the array.

You can't. You have to pass that number in to the function, use a
terminator element, or have some other way to find out. This is the same
for all arrays, whether or not they're made of structs.

Richard

Ahh... well that makes more sense - thanks.

[CBFalconer]

uidzer0 wrote:

>
I'm attempting to loop through an array of structures passed to
a function, however I'm not sure how to obtain the number of
elements in the array.

The structure is defined as:
typedef struct {
time_t creation_date;
int priority;
char *text;
} note;

And here's the function prototype:
void get_notes(note *notes);

How would I dynamically loop through *notes?

One way is to hold the pointers to note (i.e. the note* items) in
an array terminated with a NULL. Then the function might be:

void get_notes(note *notes) {
while (*notes) {
process_one_note(*notes);
notes++;
}
}

but you would be better advised to get rid of the void and return
an error indicator. Same for process_one_note()

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

[David Thompson]

On Tue, 15 Apr 2008 16:59:26 -0400, CBFalconer <cb********@yahoo.com>
wrote:

uidzer0 wrote:

I'm attempting to loop through an array of structures passed to
a function, however I'm not sure how to obtain the number of
elements in the array.

The structure is defined as:
typedef struct {
time_t creation_date;
int priority;
char *text;
} note;

And here's the function prototype:
void get_notes(note *notes);

How would I dynamically loop through *notes?

One way is to hold the pointers to note (i.e. the note* items) in
an array terminated with a NULL. Then the function might be:

OP doesn't have an array of pointers, but one pointer to an array.

void get_notes(note *notes) {
while (*notes) {
process_one_note(*notes);
notes++;
}
}

For an array of pointer you need (modulo spacing)
void get_notes (note * * notes)
then as you have it. Or (equivalent to the compiler)
void get_notes (note * notes [] )
to emphasize the array-of-pointer-ness, but downplay the fact that
array parameters/arguments are really pointers; pick your poison.

- formerly david.thompson1 || achar(64) || worldnet.att.net