struct array

[Magix]

Hi,

what is wrong with following code ?

typedef struct
{
word payLen;
datatype data[160];
} msg_type;

msg_type mymsg[10];

typedef struct
{
word myData;
} datatype;

mymsg[i].payLen = xxxx
for (k=0; k< mymsg[i].payLen; k++)
{
mymsg[i].payLen.data[k].myData = yyyy;
}

[dbtid]

Magix wrote:

Hi,

what is wrong with following code ?

typedef struct
{
word payLen;
datatype data[160];
} msg_type;

msg_type mymsg[10];

typedef struct
{
word myData;
} datatype;

mymsg[i].payLen = xxxx
for (k=0; k< mymsg[i].payLen; k++)
{
mymsg[i].payLen.data[k].myData = yyyy;
}

Well,

a) what's "word"?
b) datatype is used before it's defined.

typedef int word;
typedef struct { word myData; } datatype;
typedef struct { word payLen; datatype data[160]; } msg_type;
msg_type mymsg[10];

Now,
mymsg[i].payLen.data[k].myData
is CLEARLY wrong because payLen is a word, and you're trying to
use it as a structure.
mymsg[i].data[k].myData
is correct.

That's about all I can find.
HTH

dbtid

[Magix]

word is 16 bit unsigned integer.
My purpose is to have msg_type has a member to hold an int array of data
e.g mymsg[i].data[k].myData

so that I can have:
mymsg[0].data[0].myData = xxx
mymsg[0].data[1].myData = yyy
mymsg[0].data[2].myData = zzz
mymsg[0].data[3].myData = www
... so on

mymsg[1].data[0].myData = aaa
mymsg[1].data[1].myData = bbb
mymsg[1].data[2].myData = ccc
... so on


"dbtid" <db***@dev.null.com> wrote in message
news:sg*****************@fe2.columbus.rr.com...

Magix wrote:

Hi,

what is wrong with following code ?

typedef struct
{
word payLen;
datatype data[160];
} msg_type;

msg_type mymsg[10];

typedef struct
{
word myData;
} datatype;

mymsg[i].payLen = xxxx
for (k=0; k< mymsg[i].payLen; k++)
{
mymsg[i].payLen.data[k].myData = yyyy;
}

Well,

a) what's "word"?
b) datatype is used before it's defined.

typedef int word;
typedef struct { word myData; } datatype;
typedef struct { word payLen; datatype data[160]; } msg_type;
msg_type mymsg[10];

Now,
mymsg[i].payLen.data[k].myData
is CLEARLY wrong because payLen is a word, and you're trying to
use it as a structure.
mymsg[i].data[k].myData
is correct.

That's about all I can find.
HTH

dbtid

[Magix]

Also, how can I empty my mymsg[ ] and data[ ], in order to receive new data
? Assign ot NULL ?

*mymsg = NULL;
*data = NULL; ?
"dbtid" <db***@dev.null.com> wrote in message
news:sg*****************@fe2.columbus.rr.com...

Magix wrote:

Hi,

what is wrong with following code ?

typedef struct
{
word payLen;
datatype data[160];
} msg_type;

msg_type mymsg[10];

typedef struct
{
word myData;
} datatype;

mymsg[i].payLen = xxxx
for (k=0; k< mymsg[i].payLen; k++)
{
mymsg[i].payLen.data[k].myData = yyyy;
}

Well,

a) what's "word"?
b) datatype is used before it's defined.

typedef int word;
typedef struct { word myData; } datatype;
typedef struct { word payLen; datatype data[160]; } msg_type;
msg_type mymsg[10];

Now,
mymsg[i].payLen.data[k].myData
is CLEARLY wrong because payLen is a word, and you're trying to
use it as a structure.
mymsg[i].data[k].myData
is correct.

That's about all I can find.
HTH

dbtid

[CBFalconer]

Magix wrote:

word is 16 bit unsigned integer.
My purpose is to have msg_type has a member to hold an int array of data
e.g mymsg[i].data[k].myData

..... snip ....

Another topposter. To be ignored until he learns.

--
Chuck F (cb********@yahoo.com) (cb********@worldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net> USE worldnet address!

[kal]

"Magix" <ma***@asia.com> wrote in message news:<40**********@news.tm.net.my>...

what is wrong with following code ?
It is easier to state what is not wrong.
typedef struct
Ok.
{
Ok. Spelled correctly, I think.
word payLen;
datatype data[160];
God only knows what these two lines mean.
What are "word" and "datatype"?
} msg_type;
Ok.
msg_type mymsg[10];
Ok.
typedef struct
{
word myData;
} datatype;
No idea what "word" means!
mymsg[i].payLen = xxxx
What are "i" and "xxxx" ?
for (k=0; k< mymsg[i].payLen; k++)
{
mymsg[i].payLen.data[k].myData = yyyy;
Is "payLen" a structure/union that contains an array
of structures/unions named "data" each of which in
turn contain an element named "myData"?

What is "yyyy"?
}

Ok.
The following code may compile but what it does is
not clear to me.

<code>

typedef unsigned short word;

typedef struct
{
word myData;
} datatype;

typedef struct
{
word payLen;
datatype data[160];
} msg_type;

msg_type mymsg[10];

int main(void)
{
int i, k;

i = 1234;
i = (i < 0) ? 0 : ((i > 9) ? 9 : i);

mymsg[i].payLen = 1234;
if (mymsg[i].payLen > 160)
mymsg[i].payLen = 160;

for (k=0; k< mymsg[i].payLen; k++)
{
mymsg[i].data[k].myData = 5678;
}

return 0;
}

</code>

[Eric Sosman]

Magix wrote:

Hi,

what is wrong with following code ?
[snipped; see up-thread]

The biggest problem with this code is that it
isn't the code that's giving you trouble. Instead,
you've posted some pseudo-code that you think is
"something like" the code that's giving you trouble.
But the pseudo-code is riddled with errors -- some
of them may be the sources of your difficulty, but
others were certainly introduced by the process of
"pseudo-codification." I'm not going to waste time
trying to figure out which is which in such a mess.

Post the *actual* code that's giving you trouble,
after snipping it down to the smallest possible
complete demonstration of your problem. Remember:
since you don't understand the error (or you wouldn't
be asking about it), you are in a poor position to
decide what features of your code are and are not
relevant.

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

[Al Bowers]

Magix wrote:

Also, how can I empty my mymsg[ ] and data[ ], in order to receive new data
? Assign ot NULL ?

*mymsg = NULL;
*data = NULL; ?

From reading your posts, it is really a guess, but, I believe that
you want a struct, type msg_type, that has a member, type datatype *,
that points to an array of datatype. Also, a member, type word, that
indicates the count of the number elements of the array.

You can make your struct
typedef struct
{
word payLen;
datatype *data;
}

Usage:

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

typedef unsigned word;

typedef struct
{
word myData;
} datatype;

typedef struct
{
word payLen;
datatype *data;
} msg_type;

int AddMsgType(msg_type *p, unsigned value);
void PrintMsgs(msg_type *p);
void FreeMsgs(msg_type *p);

int main(void)
{
msg_type my_msg = {0};

AddMsgType(&my_msg,56);
AddMsgType(&my_msg,72);
puts("\tMessages");
PrintMsgs(&my_msg);
FreeMsgs(&my_msg);
puts("\n\tNew Messages");
AddMsgType(&my_msg,2);
AddMsgType(&my_msg,1);
PrintMsgs(&my_msg);
FreeMsgs(&my_msg);
return 0;
}

int AddMsgType(msg_type *p, unsigned value)
{
datatype *tmp;

if((tmp = realloc(p->data,
(p->payLen+1)*(sizeof *tmp))) == NULL)
return 0;
p->data = tmp;
p->data[p->payLen++].myData = value;
return 1;
}

void PrintMsgs(msg_type *p)
{
unsigned i;

for(i = 0; i < p->payLen; i++)
printf("p->data[%u].myData = %u\n",i,p->data[i].myData);
return ;
}

void FreeMsgs(msg_type *p)
{
free(p->data);
p->data = NULL;
p->payLen = 0;
return;
}
--
Al Bowers
Tampa, Fl USA
mailto: xa******@myrapidsys.com (remove the x to send email)
http://www.geocities.com/abowers822/

[Martin Ambuhl]

Magix wrote:

Hi,

what is wrong with following code ?

typedef struct
{
word payLen;
datatype data[160];
} msg_type;

msg_type mymsg[10];

typedef struct
{
word myData;
} datatype;

mymsg[i].payLen = xxxx
for (k=0; k< mymsg[i].payLen; k++)
{
mymsg[i].payLen.data[k].myData = yyyy;
}

/* mha:
* "what's wrong?"
* (1) using a type with no meaning in C ('word')
* (2) using the type 'datatype' before it is defined.
* (3) using the variables 'i', 'xxxx', 'yyyy', and 'k' with no declaration
* (4) failing to have a main function
* (5) omitting ';' between statements
* (6) treating the 'data' member of a msg_type struct as if it were a
* member of a struct 'payLen' which is in fact a scalar member of
* the msg_type struct.
* (7) making no effort to learn C, resulting in nonsense code.
*/

typedef unsigned long word; /* mha: added */

typedef struct
{
word myData;
} datatype; /* mha: moved up to here */

typedef struct
{
word payLen;
datatype data[160];
} msg_type;

msg_type mymsg[10];

int main(void)
{ /* mha: added */
unsigned i = 0, k; /* mha: added */
unsigned xxxx = 0, yyyy = 0; /* mha: added */
mymsg[i].payLen = xxxx; /* mha: added ';' */
for (k = 0; k < mymsg[i].payLen; k++)
mymsg[i].data[k].myData = yyyy; /* mha: fixed */

return 0; /* mha: added */
} /* mha: added */

[Martin Ambuhl]

Magix topposted:

Also, how can I empty my mymsg[ ] and data[ ], in order to receive new data
? Assign ot NULL ?

*mymsg = NULL;
*data = NULL; ?

Learn not to toppost.
And you can overwrite existing values. There is no need to "empty"
first. What time between 9 and 10 AM today did you decide to start
learning to program?

[Joe Wright]

Magix wrote:

Hi,

what is wrong with following code ?

typedef struct
{
word payLen;
datatype data[160];
} msg_type;

msg_type mymsg[10];

typedef struct
{
word myData;
} datatype;

mymsg[i].payLen = xxxx
for (k=0; k< mymsg[i].payLen; k++)
{
mymsg[i].payLen.data[k].myData = yyyy;
}

Is this a contest? Is there a prize? How many errors must I
identify? Is it C? Where's 'int main()'? Who do you think you are?
--
Joe Wright mailto:jo********@comcast.net
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[E. Robert Tisdale]

Something that calls itself Magix wrote:

What is wrong with following code? cat code.c typedef struct msg_type {
word payLen;
datatype data[160];
} msg_type;

msg_type mymsg[10];

typedef struct datatype {
word myData;
} datatype;

mymsg[i].payLen = xxxx
for (k=0; k< mymsg[i].payLen; k++) {
mymsg[i].payLen.data[k].myData = yyyy;
}
gcc -Wall -std=c99 -pedantic -c code.c

code.c:2: error: syntax error before "word"
code.c:2: warning: no semicolon at end of struct or union
code.c:3: warning: type defaults to `int' \
in declaration of `data'
code.c:3: error: ISO C forbids data definition \
with no type or storage class
code.c:4: error: syntax error before '}' token
code.c:4: warning: type defaults to `int' \
in declaration of `msg_type'
code.c:4: error: ISO C forbids data definition \
with no type or storage class
code.c:6: error: syntax error before "mymsg"
code.c:6: warning: type defaults to `int' \
in declaration of `mymsg'
code.c:6: error: ISO C forbids data definition \
with no type or storage class
code.c:9: error: syntax error before "word"
code.c:9: warning: no semicolon at end of struct or union
code.c:10: warning: type defaults to `int' \
in declaration of `datatype'
code.c:10: error: ISO C forbids data definition \
with no type or storage class
code.c:12: error: `i' undeclared here (not in a function)
code.c:12: error: syntax error before '.' token