Linked list printing & adding elements - c

Question

So the idea is I have a Doubly linked list defined as a struct
struct Node
{
struct Node *next;
struct Node *prev;
char value[5];
};
struct DoubleLinkedList
{
int size;
struct Node *head;
struct Node *tail;
};
and I'm inserting into the list using the InsertionSort function. I pass the pointer to my Doubly Linked list as a parameter to that and it gets modified with the addition of a new 4 character string node to the list(lexicographically sorted Linked list). I then print the linked list with the addition of each string node.
The printing is proving to be problematic. Right now, with the code below, the output is always something like (assume the strings being inserted at every step are aaaa,bbbb,cccc...)
aaaa
bbbb -> bbbb
cccc -> cccc -> cccc
For some reason the linked list structure is changing each and every node to the value of the new string to be inserted; I have no idea why! And also, if I try shifting the print block to the main function, it prints out gibberish.
int main()
{
struct DoubleLinkedList strings;
while (1)
{
sleep(1);
char s[5];
GenerateRandomString(s,4);
InsertionSort(&strings, s);
}
return 0;
}
void InsertionSort(struct DoubleLinkedList *sorted, char *randomstring)
{
struct Node new;
strcpy(new.value,randomstring);
printf("Newvalue %s\n", new.value);
if ((*sorted).size == 0)
{
new.next = NULL;
new.prev = NULL;
(*sorted).head = &(new);
(*sorted).tail = &(new);
}
else
{
printf("TEST %s\n", (*(*sorted).head).value);
struct Node *current;
current = (*sorted).head;
printf("CURRENT %s\n", (*current).value);
while (strcmp(randomstring,(*current).value) > 0)
{
current = (*current).next;
if (current = NULL)
{
break;
}
}
new.next = current;
if (current != NULL)
{
new.prev = (*current).prev;
if ((*current).prev != NULL)
{
(*(*current).prev).next = &(new);
}
else
{
(*sorted).head = &(new);
}
(*current).prev = &(new);
}
else
{
new.prev = (*sorted).tail;
(*((*sorted).tail)).next = &(new);
(*sorted).tail = &(new);
}
}
(*sorted).size++;
struct Node *printing;
printing = (*sorted).head;
int i;
for (i = 0; i < (*sorted).size - 1; i++)
{
printf("%s -> ", (*printing).value);
printing = (*printing).next;
}
printf("%s\n",(*printing).value);
}

Answer 1

You haven't allocated memory for the value in
strcpy(new.value,randomstring);
you're lucky your subsequent printf works.
You can do for example
new.value = strdup(randomstring);
(don't forget to release memory with free(new.value) when you delete your Node if you do so, because strdup calls malloc).

Answer 2

Er, you're not allocating memory for new either, so when you exit InsertionSort, the Node is dangling.
Should be in InsertionSort
new = (struct Node *)malloc(sizeof(struct Node));
then adjusting everything to use a pointer (that is new -> stuff instead of new.stuff and new instead of &new).
Also in main strings.size in uninitialized
strings.size = 0;
seems missing.
Last one, when you write
if (current = NULL)
I think you mean
if (current == NULL)
(in some C tradition, you'd write if (!current))
With these modifications, it seems to work.