Re: Variable array sizes as members ?

Hello fellows,

I would like to thank every one of you for your help!

Sometimes its hard for me to explain what I am looking for because the
further I go the more I am getting trapped in a certain method of
programmtion. Its not the fact that I want to know how to do this or to do
that... it has now become can I do this and can I do that and fit it into the
project's coding architecture. That's why sometimes I want a certain help
from you guys but then I seem to be stuck in how to integrate the help or
the sample provided into the whole thing while following the established and
specific rules so it all works together. That being said,

Barry and Scott have talked about making my array member a pointer so it can
point to dynamic space and store my data there. Okay, I am sure this is the
way things should be done. But I will show you a a sample program and I don't
know where I would do the malloc for this. Maybe because I haven't shown a
cleare example yet and probably this is what is confusing me.


Scott can let me know how scope trouble would be present in the sample code
I will be showing later on.

Alex, your solution seems to be the most conformant to well written code. I
will have to look into that. Thanks.

David, you have precisely answered my question, the help I was seeking was
exactly what you came up with and I tried it, fit into my project and it
compiles... I haven't tested it yet, but I am pretty sure it will work.

Here is my C code.... tested in VC++ and compiles without error.

==========================================
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct tag_list60
{
long storage[60];
}list60;

typedef struct tag_list30
{
long storage[30];
}list30;

typedef struct tag_list10
{
long storage[10];
}list10;

typedef struct tag_lb_table
{
long lb_items[5];
struct tag_list10 *x;
struct tag_list30 *y;
struct tag_list60 *z;
}lb_table;

typedef struct tag_lb
{
struct tag_lb_table *dc;
//...other members here
}lb;

// Other parameters passed in this function are not shown!
lb* create_obj(
            lb *obj_lb,
            lb_table *lb)
{
obj_lb = malloc (sizeof (struct tag_lb_table));
obj_lb->dc = lb;
//...Other setups here not shown
return obj_lb;
}

store_to_eeprom(lb *objLb, int eeprom_bank)
{
// funtion which stores storage
// informations to eeprom
}

int main()
{
lb MyRef3;
lb *objLb1 = &MyRef3;

list10 storage10[10]; // Up to 10 MAX
list30 storage30[30]; // Up to 30 MAX
list60 storage60[60]; // Up to 60 MAX

lb_table lb_arr[] = {
{ 185, 184, 183, 0, 0, storage10, NULL, NULL},
{ 111, 211, 0, 0, 0, NULL, storage30, NULL,},
{ 185, 200, 43, 22, 150, NULL, NULL, storage60},
{ 185, 22, 243, 0, 0, NULL, NULL, NULL},
{ 10, 20, 0, 0, 0, NULL, storage30, NULL,},
{ 1, 222, 200, 0, 0, NULL, NULL, NULL},
{ 85, 4, 204, 11, 28, NULL, NULL, NULL},
{ 1, 0, 0, 0, 0, NULL, NULL, NULL},
{ 15, 27, 43, 99, 0, NULL, NULL, NULL},
};

objLb1 = create_obj(objLb1, lb_arr);

// So I can do stuff like this!
// For 10 MAX
objLb1->dc[0].x->storage[0] = 201;
objLb1->dc[0].x->storage[1] = 501;
//...
objLb1->dc[0].x->storage[9] = 21;

store_to_eeprom(objLb1, 0);

// For 30 MAX
objLb1->dc[1].y->storage[0] = 64;
objLb1->dc[1].y->storage[1] = 78;
//...
objLb1->dc[1].y->storage[29] = 521;

store_to_eeprom(objLb1, 1);

// For 60 MAX
objLb1->dc[2].z->storage[0] = 203;
objLb1->dc[2].z->storage[1] = 506;
//...
objLb1->dc[2].z->storage[59] = 28;

store_to_eeprom(objLb1, 2);

// For 30 MAX
objLb1->dc[4].y->storage[0] = 4;
objLb1->dc[4].y->storage[1] = 7;
//...
objLb1->dc[4].y->storage[29] = 52;

store_to_eeprom(objLb1, 4);

free(objLb1);

return 0;
}
==========================================

I like to pick and choose the array according to the required size when I
fill out my
lb_table table. Then the program knows to store the informations in the
right array.

*** It would be nice to do the above by simply having one:

typedef struct tag_list_x
{
long *storage;
}listx;

structure where I can store a pointer to a malloc space in memory. The
problem is, how can I do this at the time I am filling out the lb_table
table? I know how malloc works, but I am just drawing a blank here on how I
could accomplish the same convinience of the above sample but with a dynamic
array for every record as I fill out my table!

I don't know if I am explaining this right!

But the idea here is to fill out the table "lb_table" for 5 items and when
the odd time comes where I need more than 5 items, I select a storage array
space to accomodate eeprom data for 6 to 10 items, 11 to 30 items or 31 to 60
items as required for that specific record.

PS I would be happy with the above code, but if there is a little
modification or insight as to weather I can replace the 3 storage structures
by one, that would be great.

Thanks all for you help!

--
Best regards
Roberto

"David Wilkinson" wrote: