Recursive struct

Question

Do I need to use typedef in order to build recursive structs? I tried to use the following code without success:

struct teste
{
    int data;
    int data2;
    struct teste to_teste;
};

You can't have directly recursive structures in C; they require an infinite amount of storage space. You can have structures that contain pointers to themselves. — Jonathan Leffler, Nov 22 '12 at 01:21

score 14 · Accepted Answer · answered Nov 22 '12 at 01:19

14

To build recursive structs you do not need typedef.

You will have to convert the struct object into a struct pointer object.

like this:

struct teste{
  int data;
  int data2;
  struct teste *to_teste;
};

answered Nov 22 '12 at 01:19

Aniket Inge

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@user1843665 that's what stack overflow is for. :-) – Aniket Inge Nov 22 '12 at 01:22
Oh, i see.I would make a reference to data2 in the inner struct by : struct teste testing; testing.to_teste->data2 ? – user1843665 Nov 22 '12 at 01:26
don't forget to `malloc()` the `to_teste` pointer before using `testing.to_teste->data2;` – Aniket Inge Nov 22 '12 at 01:27

CCoder · Answer 2 · 2012-12-18T06:00:17.043

6

You CANNOT have the same structure inside itself. If you do that then size of that structure becomes indefinite. So that is not allowed.

Instead you can have a pointer to the same structure inside itself to solve your purpose. This will work because size of a pointer is known to the compiler and the structure has a definite size now.

edited Dec 18 '12 at 06:00

answered Nov 22 '12 at 03:23

CCoder

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Recursive struct

2 Answers2