Hi, I need to develop a menu system for a project of mine. The menu
will be displayed on a character LCD display driven by ARM7
Microcontroller . For this purpose i wish to construct a structure in C
which will contain a the following -
struct menu
{
int n (no. of elements in menu);
char menu_items[20][q]; (This will contains the strings to be
displayed on the LCD, 20 characters and n lines
funcptr fptr; (Pointer to the corresponding menu function)
}
the array "menu_items " will always have 20 character strings but the
no. of them 'q' will differ from each menu screen. the no. of strings
will be defined in "int n". I will be using this struct to implement
const structs which i will be defining with all the menu screen
information.
From googling around i found variable length arrays cannot be
implemented with in structures. I also found that the structure size
should be known at compile time(i dont want to use malloc). My menu
items will be known at compile time. how do i implement this?
Thanks.
Sep 14 '08
27  3300 
On Mon, 15 Sep 2008 13:49:07 +0000, Richard Heathfield
<rj*@see.sig.in validwrote:
>Ben Bacarisse said:
>Nick Keighley <ni************ ******@hotmail. comwrites:
>>On 15 Sep, 10:17, Richard Heathfield <r...@see.sig.i nvalidwrote:
Nick Keighley said:
On 14 Sep, 17:45, Richard Heathfield <r...@see.sig.i nvalidwrote:
...but by outlawing malloc, you make it very difficult!
it doesn't seem *that* difficult!
obviously it *should* have looked difficult...
Can someone explain what the problem is? The OP started off thinking
that char strings[n][20]; would do but we know it won't. One can
waste a little and use char (*strings)[20]; or one can just have char
**strings; and initialise that with a bunch of literals via a named
array (as posted by at least three people, I think).
It seems that I am missing why this is considered hard or a problem if
malloc is not allowed.
Probably my fault. I only meant that, with malloc, it would have been easy
to provide a very efficient solution. I think that, without it, the
solution is clunkier, harder to code, and less efficient. Given the
probable origin of the question as homework, I am reluctant to provide the
source that might conceivably explain what I mean far better than I can
explain it in English.
The OP has already explained that it is not homework, and has
(briefly) explained the context and why he doesn't want to use
malloc. Since you seem to have missed it, here is the relevant
passage:
"The reason i dont want to use malloc is that the all the menu
items/elements are defined at compile time and will be stored
like a lookup table in the flash code memory on the
microcontroller . So there's no dynamic allocation. If i were to
use malloc the space would allocated from onchip RAM of which i
have only 64KB. the flash has a more generous 256KB."
Richard Harter, cr*@tiac.net http://home.tiac.net/~cri, http://www.varinoma.com
Save the Earth now!!
It's the only planet with chocolate.
Thank you all for your replies and code snippets, i will try your
ideas when i start with coding today...
--
aramosfet
Nick Keighley wrote:
CBFalconer <cbfalco...@yah oo.comwrote:
>aravind wrote:
>>Hi, I need to develop a menu system for a project of mine. The
menu will be displayed on a character LCD display driven by ARM7
Microcontroll er. For this purpose i wish to construct a structure
in C which will contain a the following -
Besides the fact that this appears to be homework, it is
off-topic. c.l.c deals with the C language, as defined in the
various C standards. comp.arch.embed ded might be a better place,
if it wasn't homework.
don't talk rubbish. The question is on-topic.
Oh? You think ARM Micros and char LCD displays are on-topic?
Possibly they are never referenced again, but reading the post to
this point doesn't make that evident.
--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home .att.net>
Try the download section.
On Sep 15, 11:07 pm, CBFalconer <cbfalco...@yah oo.comwrote:
Nick Keighley wrote:
CBFalconer <cbfalco...@yah oo.comwrote:
aravind wrote:
>Hi, I need to develop a menu system for a project of mine. The
menu will be displayed on a character LCD display driven by ARM7
Microcontrolle r. For this purpose i wish to construct a structure
in C which will contain a the following -
Besides the fact that this appears to be homework, it is
off-topic. c.l.c deals with the C language, as defined in the
various C standards. comp.arch.embed ded might be a better place,
if it wasn't homework.
don't talk rubbish. The question is on-topic.
Oh? You think ARM Micros and char LCD displays are on-topic?
Possibly they are never referenced again, but reading the post to
this point doesn't make that evident.
His question was on-topic. The background information was not.
Similar to:
I have many cats and I want an array to keep all their names.
I have this:
char **cat_names;
But I'm confused about using malloc with this... Can anyone help?
Cats are not on-topic. The question is.
CBFalconer <cb********@yah oo.comwrites:
Nick Keighley wrote:
>CBFalconer <cbfalco...@yah oo.comwrote:
>>aravind wrote:
Hi, I need to develop a menu system for a project of mine. The
menu will be displayed on a character LCD display driven by ARM7
Microcontrol ler. For this purpose i wish to construct a structure
in C which will contain a the following -
Besides the fact that this appears to be homework, it is
off-topic. c.l.c deals with the C language, as defined in the
various C standards. comp.arch.embed ded might be a better place,
if it wasn't homework.
don't talk rubbish. The question is on-topic.
Oh? You think ARM Micros and char LCD displays are on-topic?
Possibly they are never referenced again, but reading the post to
this point doesn't make that evident.
No, it doesn't. Reading past that point does. If you don't have time
to read more than the first paragraph of a post, I'm surprised you
have time to post a followup claiming that it's off-topic.
aravind's was topical. He provided some background regarding the
motivation for what he's trying to do (something that too few posters
do). The fact that you didn't realize it was topical is your fault,
not his.
I don't recall seeing an off-topic post for which you, but nobody
else, pointed out that it was off-topic. I think you can safely take
a break. We've got it covered.
--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
In article <ln************ @nuthaus.mib.or g>,
Keith Thompson <ks***@mib.orgs ensibly chided our good friend CBF thusly:
....
>aravind's was topical. He provided some background regarding the
motivation for what he's trying to do (something that too few posters
do). The fact that you didn't realize it was topical is your fault,
not his.
I don't recall seeing an off-topic post for which you, but nobody
else, pointed out that it was off-topic. I think you can safely take
a break. We've got it covered.
Well done, sir! I see you and Richard (*) are finally on the same side
of an issue. That puts you on the right side for a change.
(*) He whom you often refer to as "he who has no last name" (or some
such piffle)
CBFalconer said:
Nick Keighley wrote:
>CBFalconer <cbfalco...@yah oo.comwrote:
>>aravind wrote:
Hi, I need to develop a menu system for a project of mine. The
menu will be displayed on a character LCD display driven by ARM7
Microcontrol ler. For this purpose i wish to construct a structure
in C which will contain a the following -
Besides the fact that this appears to be homework, it is
off-topic. c.l.c deals with the C language, as defined in the
various C standards. comp.arch.embed ded might be a better place,
if it wasn't homework.
don't talk rubbish. The question is on-topic.
Oh? You think ARM Micros and char LCD displays are on-topic?
No, but they are merely incidental - the question is on-topic.
If you must play topic-cop, please play good cop, not dumb cop.
Possibly they are never referenced again, but reading the post to
this point doesn't make that evident.
Try reading the *whole* article! It's only 21 lines, for Cthulhu's sake!
--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999
On Sep 16, 1:49*am, Richard Heathfield <r...@see.sig.i nvalidwrote:
Probably my fault. I only meant that, with malloc, it would have been easy
to provide a very efficient solution. I think that, without it, the
solution is clunkier, harder to code, and less efficient.
I think it's is clunkier, harder to code, and
less efficient with malloc!
(Assuming that all of the table entries are
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