Thread: Trouble using Insertion Sort on Double Linked List

Thank you, this makes a lot of sense.
I'm getting two problems on line 96 that have to do with memory allocation:
'use of uninitialized value of size 8' and 'invalid write of size 8'

I have been seeing these pop up but I'm still not entirely clear on what they mean, but it looks like this is the cause of the segmentation fault I'm getting.

Line 96? Of what version? Surely you've changed your code since the last posting. Please the updated version.

EDIT: And yes, they seem to indicate memory errors. Do you know how to use a debugger? It would really help here. The exact details depend on which debugger you use, which depends (somewhat) on which compiler/compiler options you use.

I have been using valgrind to find these errors and problems. The submission deadline for this assignment actually just passed and I had to submit an incomplete non-working version for now. I am going to ask my professor for help tomorrow; he said he may extend the deadline. I will post back on here when I have more information and have hopefully resolved some of the problems. Thanks for all your help.

With the help of GDB, my professor, and a friend, I managed to finally get a working Insertion Sort function.

Code:

void Insertion_sort(List * list)
{
    Node * index;
    Node * node;
    Node * temp;
    Node * temp2;

    for(index = list->first; index != NULL && index->next != NULL; index = index->next)
    {
        if(index->ID > index->next->ID && &index->next->ID != NULL)
        {
            node = remove_node(list, index->next);
            temp = index;

            while(temp->ID > node->ID)
            {
                if(temp != list->first)
                {
                    temp = temp->prev;
                } else {
                    break;
                }
                
            }
            if(temp->ID < node->ID)
            {
                temp2 = temp->next;
                node->prev = temp;
                node->next = temp2;
                temp->next = node;
                temp2->prev = node;    
            } else {
                node->next = temp;
                list->first = node;
                temp->prev = node;
            }
            index = index->prev;
        }
        
        if(index == list->last)
        break;
    }
}