segmentation fault (Core dumped) error on Dynamic array

Question

I am having this issue when trying to build my dynamic array, I think that there is mystake on realloc function or something, would appreciate if you can give me a hand on it. I am able to enter the names the first time but the issue start when Im doing it the second time

typedef struct {
 char nom[30], prenom[20];
 int age;
 } ITEM;
 void Lire(ITEM **items, int *nb_items)
 {
 int i = 0;
 printf("* Entrer les donnees et taper . pour terminer\n\n");
 for (i = 0; TRUE; i++) 
 {
 ITEM *temp = (ITEM *) realloc(*items, ((i + 1) * sizeof(ITEM)));
 if (temp == NULL)
 {
 free(*items);
 printf("Il n'y a pas de memoire! \n");
 exit (0);
 }
 *items = temp;
 printf("> nom : ");
 scanf("%s", (*items[i]).nom);
 if ((*items[i]).nom[0] == '.')
 break;
 printf("> prenom : ");
 scanf("%s", (*items[i]).prenom);
 }
 }
int main(int argc, char *argv[])
{
 ITEM *items;
 int nb_items=0;
 items = (ITEM *) malloc(sizeof(ITEM));
 if(items == 0)
 {
 printf("Il n'y a pas de memoire! \n");
 exit (0);
 }
 Lire(&items, &nb_items);
 free (items);
 exit(0);
}

• PaulMcKenzie: You tagged this question as C++. Why are you not using std::vector?
• deviantfan: You can´t use realloc alone. malloc and free are there to use too.
• Daniel Chaparro: thanks, I am using them in the main this is just a function to fill my array, should I use malloc and free here as well?
• Weather Vane: Are you typing a name that is too long? You are not protecting your strings from overrun. Try scanf("%29s", (*items[i]).nom);
• Valeri Atamaniouk: Actually realloc can work just fine without malloc/free. If the initial value NULL, realloc works as malloc. If the requested size is 0, realloc works as free.

Answer 1

You problem is in operator precedence: *items[i] evaluates to items[i][0] and you want items[0][i], which is:

(*items)[i]

Answer 2

Array subscript access binds tighter than *. This causes *items[i] to be interpreted as *(items[i]), for example in this statement:

scanf("%s", (*items[i]).nom);

So items is accessed as if it would be an array of pointers to ITEM. In reality it is a pointer to an array of ITEM structs, and should be accessed like this:

scanf("%s", (*items)[i].nom);

Answer 3

to make life easier i would do

 *items = temp;
 ITEM *current = &temp[i];
 printf("> nom : ");
 scanf("%s", current->nom);
 ...etc

makes the code easier to read and simplifies the whole operator precedence isuuse

• Daniel Chaparro: actually this issue was solved today with your help, the names are being inserted into the array, the isse is reallocating memory I think as I am getting this segmentation Fault(Core dumped) when I need to enter the second block of info