Linked List search() and delete() trouble

[Judas1012]

Got a bit of trouble figuring out where my code is going wrong for a Linked List in C (not C++)...

Both removefirst() and freeNode() work correctly. There's also a few lines of stderr output as debugging, so I can tell how far the methods get before the error. It seems to error when trying to delete a node other than the first node in the list.

nodePtr is a typedef of a nodeType *, and nodeType is a struct: {int info; nodeType * right}.

Can anyone shed some light on what pointer or variable I've got screwed up? I know I've got the algorithm right, it's just a bit of confusion over which pointer isn't getting the correct value... it seems as though the lptr (lead pointer) and tptr (trailing pointer) aren't being assigned correctly in the search() method, as they seem to always return with their original values (lptr = front, tptr = NULL).

boolean search(nodePtr front, nodePtr * lptr, nodePtr * tptr, infoType target)
/* return true if target is in the list, false otherwise */
/* lptr should point to node where target found, and */
/* tptr should point to the trailing node or be NULL */
{
    *lptr = front;
    *tptr = NULL;

    while ((*lptr != NULL) && (front->info != target))
    {
        tptr = lptr;
        *lptr = (*lptr)->right;
    }

    return (lptr != NULL);
}

void deleteNode (nodePtr * front, infoType target)
/* delete the node containing target */
{
    nodePtr tptr, lptr;
    
    if (search(*front, &lptr, &tptr, target) == true)
    {
        fprintf(stderr, "FOUND!\n");
        
        if ((tptr == NULL) && (lptr != NULL))
        {
            fprintf(stderr, "Deleting first node!\n");
            removefirst(front);
        }
        else
        {
            fprintf(stderr, "Deleting node other than first!\n");
            tptr->right = lptr->right;
            freeNode(lptr);
        }
    }
}