C - problem with insert in linked list

[WarmDismalAgony]

hey, can anyone figure out why this insert function is setting all nodes in the list to have the same item?

void insert_list (list_ref list, list_item item) {
    listnode_ref new = malloc (sizeof (struct listnode));
    assert (is_list (list));
    assert (new != NULL);
    new->tag = listnode_tag;
    new->item = item;
    if (list->head == NULL) {
       list->head = new;
       list->last = new;
       list->curr = new;
    }else{
       new->prev = list->last;
       list->last->next = new;
       list->last = new;
       list->curr = new;
    };
}
 

i cant figure it out for the life of me. other than that problem it seems to be working fine - it creates a new node and sticks it on the list, and it appears that the links work, too. any help would be GREATLY appreciated.. i've been trying to figure this out for like 2 hours -_- i think i must be missing something obvious, but i have no idea what. i know for sure the problem has to be in this function, though (after a LOT of debug prints to pinpoint it).

[gpraghuram]

I dont know how you have defined your doubly linked list.
But the logic would be

If head == NULL
head = tail = newnode;
else
tail->next=newnode;
newnode->prev = tail;
tail=newnode



Raghuram

[WarmDismalAgony]

yeah thats exactly what my code is except for tail->next=newnode and newnode>prev=tail are switched (which shouldnt make a difference right?)

so.. i dont see how it can be this function thats the problem.. yet i stuck a print statement for the item right before the insert function is called, and a debug function that shows all the items right after the insert function is called...

the print statement shows different items being called in and the debug shows all the items being set to whatever the most recent one was (and a new node is added every time).

any ideas?

[gpraghuram]

yeah thats exactly what my code is except for tail->next=newnode and newnode>prev=tail are switched (which shouldnt make a difference right?)

so.. i dont see how it can be this function thats the problem.. yet i stuck a print statement for the item right before the insert function is called, and a debug function that shows all the items right after the insert function is called...

the print statement shows different items being called in and the debug shows all the items being set to whatever the most recent one was (and a new node is added every time).

any ideas?

I can understand other lines except this
What does this line do?
list->last->next = new;

I think issue is with this line

Raghuram

[WarmDismalAgony]

I can understand other lines except this
What does this line do?
list->last->next = new;

I think issue is with this line

Raghuram

thats the equivalent of your tail->next=newnode

[WarmDismalAgony]

ok the problem was not creating a new space in memory for each item. i'm an idiot. problem solved.