CODEWITHSUNDEEP
clinked-list
gn66
gn66

Reputation: 863

Delete a item from linked list in c

How can I delete a Item from a linked list in c.

typedef struct
{
    int n;
    struct item *nexI;

} item;


#define na 1000
int n, j;

I have in my main:

item * list[na];

n = 5;

for(j = 0; j < na; j++)
    remove_elem(list, n, j);

now my function remove_elem:

void remove_elem(item * list[], int n, int pos)
{
    int i;
    item * aux;
    item * sec;


    aux = list[pos]->nexI;

    if(aux == NULL)
        return;
    else
    {
        sec = (item *)aux->nexI;

        if(aux->n == n)
        {
        list[pos]->nexI = sec;
            return;
        free(aux);
        }

        while(sec != NULL)
        {

            if(sec->n == n)
            {
                aux->nexI = sec->nexI;
                free(sec);
                return;
            }
        aux = (item *) aux->nexI;
        sec = (item *) sec->nexI;
        }
    }

}

but this code is giving me a segmentation fault and i cant notice why, can u figure it what I'm doing wrong here?

Upvotes: 1

Views: 517

Answers (1)

Some programmer dude
Some programmer dude

Reputation: 409482

Going strictly by your code, I would wager a guess that it's about uninitialized pointers.

First when you declare your array of pointers, you need to initialize all pointers to NULL:

item * list[na] = { NULL };

Then you should check for NULL pointers in all your functions:

void remove_elem(item * list[], int n, int pos)
{
    if (list[pos] == NULL)
        return;

    /* ... */
}

And of course, when you allocate a new node to put in the list, you of course have to set the nexI pointer to NULL as well, or checks like if(aux == NULL) will not work.

Upvotes: 2

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