pointer to a struct

HI Ng.

I got a littel problem with a pointer to a struct

Code:

---

struct Template {
struct Template const *NextMenu;
};

extern struct Template const MenuA;

struct Template const *PointerMenuA[] ={&MenuA,0};

struct Template const MenuA = {PointerMenuA[0]};

---

In my array "*PointerMenu" I got all my addresses, on all my menus,
in this example I only have one.

I want to get the address on "MenuA" by accessing my struct "MenuA",
but it seems impossible, I had thought of something like this, I
know it's wrong, so I hope that you can help me.

Code:

---

void main()
{
struct Template const *Pointer;

Pointer = &MenuA.NextMenu; // This is the line
}

---

I know that I can get the right address by doing this, but it is not good enough.

Code:

---

Pointer = PointerMenuA[0];

---

I hope you understand my question, if not please leave a message, and I will try to explain it better :confused:
Thank you in advance.
Søren Panduro - Denmark

Use -> when addressing attributes of pointers to structs where you would normally use .
e.g.

Code:

---

foo *bar = malloc(sizeof(foo));

bar->next = malloc(sizeof(foo));

---

hope this helps.

Hi
If I do like this:

Code:

---

Pointer = &MenuA;
Pointer = Pointer -> NextMenu;

---

I still get the address of the "PointerMenuA" array? :confused:

Any other ideas? Or maybe I just need a little more help, to see light :D

Don't use void main().

Quote:

---

I want to get the address on "MenuA" by accessing my struct "MenuA",
but it seems impossible

---

Like this?

Code:

---

struct Template *pointer = &MenuA;

---

Quote:

---

Like this?
Code:
struct Template *pointer = &MenuA;

---

Yes that right, but I have more than one address in my array, that’s why I have to access the address of my menus through the array.

Something like that: (still wrong) :(

Code:

---

void main()
{
struct Template const *Pointer;

Pointer = &MenuA.NextMenu; // This is the line
}

---

Code:

---

&MenuA.NextMenu

---

is the address of the "NextMenu" member, not the address stored there. Is this what you want? If you're looking for the address of the object referenced by MenuA.NextMenu, simply use

Code:

---

MenuA.NextMenu

---

(note the lack of an indirection operator ("&").

i guess this is what u wanted

Code:

---

#include<stdio.h>

struct something
{
    int data;
    struct something *some;
};

int main()
{
    struct something dosome;
    struct something *pointer;
   
    pointer = malloc(sizeof(struct something) * 2);
    dosome.data = 10;
   
    (pointer+1)->some=&dosome;
   
    printf("Address of dosome %p\n",&dosome);
    printf("Data in dosome structure %d\n",dosome.data);
    printf("The pointer structure %p\n",(pointer+1)->some);
    printf("The pointer having the same data %d",(pointer+1)->some->data);
    getchar();
    return 0;
}

/*my output
Address of dosome 0022FF70
Data in dosome structure 10
The pointer structure 0022FF70
The pointer having the same data 10
*/

---

ssharish2005

Hmm. I'd been fishing with something like this.

Code:

---

#include <stdio.h>

struct Menu
{
  const char        *title;
  struct Menu const  *next;
};

extern const struct Menu A, B, C, D;

const struct Menu *const MenuList[] = { &A, &B, &C, &D };

const struct Menu A = { "A", &D};
const struct Menu B = { "B", &C};
const struct Menu C = { "C", NULL};
const struct Menu D = { "D", &B};

int main(void)
{
  const  struct Menu *menu = MenuList[0]->next;
  while ( menu )
  {
      puts(menu->title);
      menu = menu->next;
  }
  return 0;
}

/* my output
D
B
C
*/

---

Hi.

I think we are on to something now :) , but my array is in my struct.:(

Like this

Code:

---

struct Template const MenuA = {PointerMenuA[0]};

---

And I can only access it through my struct.

In my pointer I want the address, of the menu in my array, by accessing my struct. :confused:

I got it!!!!!!!!!! :D

My *NextMenu has to be a pointer to a pointer.

Code:

---

extern struct Template const MenuA;

struct Template const **PointerMenuA[] ={&MenuA,0};
struct Template const MenuA = {&PointerMenuA[0]};


void mani()
{

pointer  = MenuA.NextMenu[0]

}

---

yes and thanks..

Quote:

---

Originally Posted by ramdal

I got it!!!!!!!!!! :D

My *NextMenu has to be a pointer to a pointer.

Code:

---

void mani()
{

---

yes and thanks..

---

Also, while mani is fine to be set to have a void return type, main is not a void function. main always returns an int.


Quzah.

Just curious, do you have a more complete snippet? I ask because what I've pieced together from your responses would not appear to be correct:

Code:

---

struct Template {
struct Template const *NextMenu;
};

extern struct Template const MenuA;

struct Template const **PointerMenuA[] = {&MenuA,0};
/*
test.c 7: [64 Error] Type mismatch (initialization) (const struct Template ** = const struct Template *)
*/
struct Template const MenuA = {&PointerMenuA[0]};
/*
test.c 11: [64 Error] Type mismatch (initialization) (const struct Template * = const struct Template ***)
*/

---

or

Code:

---

struct Template {
struct Template const **NextMenu;
};

extern struct Template const MenuA;

struct Template const **PointerMenuA[] = {&MenuA,0};
/*
test.c 7: [64 Error] Type mismatch (initialization) (const struct Template ** = const struct Template *)
*/
struct Template const MenuA = {&PointerMenuA[0]};
/*
test.c 11: [64 Error] Type mismatch (initialization) (const struct Template ** = const struct Template ***)
*/

---

Hi

it has to be like this :

Code:

---

struct Template {
struct Template const **NextMenu;
};

extern struct Template const MenuA;

struct Template const *PointerMenuA[] = {&MenuA,0};

struct Template const MenuA = {&PointerMenuA[0]};

---

Q: whar editor/complier do you use, I use one for 8-bit Zilog and I use Zilog uC, or what can you recommend?

Ah:

Code:

---

struct Template const *PointerMenuA[] = {&MenuA,0};

---

Looks fine. Thanks.

Quote:

---

Originally Posted by ramdal

Q: whar editor/complier do you use, I use one for 8-bit Zilog and I use Zilog uC, or what can you recommend?

---

I use SlickEdit and a variety of compilers. The diagnostic messages in my previous post were the output of PC-lint. And I haven't done Zilog in quite a number of years, so I have no recommendations there.