cant get this delete node working

I am having trouble with this, it works... kind of except for deleting the head and the node it deletes prints as 0 !!

Code:

---


list_t
*delete_value (list_t *list, int value) {
        node_t *ptr, *prev, *tmp;
       
        ptr = list->head;
       
                while (ptr!=NULL)
        {
       
        if (list->head->data==value)
                {
                        tmp=list->head;
                       
                        if (list->head->next!=NULL)
                        {
                                list->head = list->head->next;
                                free(tmp);
                                ptr = list->head;
                                prev = ptr;
                        }
                        else
                        {
                                list->head = list->foot = NULL;
                                free(tmp);
                        }
                }

                prev = ptr;       
       
                if (ptr->data==value)
                {
                        tmp = prev;
                        prev = ptr->next;
                        free(tmp);
                        ptr = prev;
                }
                if (ptr->data==value && ptr->next==NULL)
                {
                        tmp = prev;
                        prev = NULL;
                        free(tmp);
                        ptr = prev;
                }
                ptr = ptr->next;
        }
        return list;
}

---

can anyone tell me what im doing wrong please!

Code:

---

node *delnodebyvalue( node *n, data_t v )
{
    node *d = n;
    if( d )
    {
        node *p = d;
        for( ; d && p; p = d, d = d->next )
        {
            if( d->value == v )
                break;
        }
       
        if( d == p ) /* head */
        {
            d = d->next;
            free( p );
            p = NULL;
            n = d;
        }
        else
        if( d )
        {
            p->next = d->next;
            free( d );
            d = p;
        }
    }
    return n /* d */;
}

---

I haven't tested this, but that looks about right. That looks better.

I find your added layer of 'list' as a wrapper too hard to read this late in the evening for me. It's easier for me to just write a new one than it is to try and figure out what you've done wrong. At a quick glance, I'd say it's probably somewhere here:

Code:

---

if (ptr->data==value)
                {
                        tmp = prev;
                        prev = ptr->next;
                        free(tmp);
                        ptr = prev;
                }
                if (ptr->data==value && ptr->next==NULL)
                {
                        tmp = prev;
                        prev = NULL;
                        free(tmp);
                        ptr = prev;
                }

---

Either you're being clever here, or you've missed something here, since what your code here might do is free ptr twice, since you don't have an else there. Like I said though, you may just be doing something clever that I'm too tired to catch.


Quzah.

Can u show your struct definition please.

I can see some wried stuff there.

ssharish2005

I think quzah may be right, I will impliment that solution. The compiler showed a segmentation fault from the same area of code quzah referenced.

Here are the struct definitions:

Code:

---

typedef int data_t;

typedef struct node node_t;

struct node {
        data_t data;
        node_t *next;
};

typedef struct {
        node_t *head;
        node_t *foot;
} list_t;

---