Malloc Member Array of Struct

Question

I have a struct and an dynamic array inside the struct. I want to malloc this array but i don't really now how. I want that array void because i want the members of this array to be structs. As you can see i tried something but it doesn't really work

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

struct saf 
{
  int head;
  void **stack;
  int size;
}exp1;



void init(int n)
{

   struct saf exp1->stack = malloc(n);

}

int main()
{

 printf("Give size: ");
 scanf("%d",&exp1.size);
 init(exp1.size);

return 0;
}

what error does it give you?

γηράσκω δ' αεί πολλά διδασκόμε
– γηράσκω δ' αεί πολλά διδασκόμε

2014-03-25 00:59:41 +00:00
Commented Mar 25, 2014 at 0:59 — γηράσκω δ' αεί πολλά διδασκόμε
– γηράσκω δ' αεί πολλά διδασκόμε, Commented Mar 25, 2014 at 0:59
"ivalid type argument of '->' (have 'struct saf')"

Manuel Pap
– Manuel Pap

2014-03-25 01:01:30 +00:00
Commented Mar 25, 2014 at 1:01 — Manuel Pap
– Manuel Pap, Commented Mar 25, 2014 at 1:01

The Dark · Accepted Answer · 2014-03-25 01:07:38Z

2

exp1 isn't a pointer. Use

exp1.stack = malloc(n);

answered Mar 25, 2014 at 1:07

The Dark

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1 Comment

Manuel Pap Over a year ago

Yes this is it . Thank you so much, what a fool i am

codonnell · Accepted Answer · 2014-03-25 00:49:58Z

2

I believe you are looking for void *, e.g.,

void init (int n)
{
    exp1->stack = malloc(sizeof(void *) * n);
}

You will have to cast it when you use it.

answered Mar 25, 2014 at 0:49

codonnell

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1 Comment

Manuel Pap Over a year ago

It doesn't work,maybe i am missing something. Should i change something in struct?

Vinay · Accepted Answer · 2014-03-25 11:08:36Z

0

struct saf exp1.stack = malloc(n);

The above statement creates array of n memory locations and returns the void * pointer to the starting address. In this case stack should be single pointer i,e void *stack; If you want stack to be a double pointer i,e void **stack then you should use

exp1.stack=malloc(sizeof(void *)*n);

answered Mar 25, 2014 at 11:08

Vinay

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