You need to allocate your list by allocating each node. One way of doing that while chaining the list forward is the code below:
struct plane* list_intialize(unsigned int num)
{
struct plane *head, **pp = &head;
int i=0;
for (i=0; i<num; ++i)
{
*pp = malloc(sizeof(**pp));
setData(*pp);
pp = &(*pp)->nextPlane;
}
*pp = NULL;
return head;
}
How It Works
This uses a pointer-to-pointer to always hold the address of the location where the nextPlane dynamo node address is stored. It starts with the address of the head pointer. With each new node, pp
is filled the address of that node's nextPlane
member. Once finished, it holds the address of the last node's nextPlane
pointer, which it sets to NULL. The first node, pointed to by head
, is returned. (and yes, this works even if you passed num = 0
for the requested size, in which case you would get back zero nodes: i.e. NULL
).
Note: Don't forget, you need to free each node when releasing the list, extracting a single node out, etc. For example, to delete an entire list:
void list_delete(struct plane **lst)
{
while (*lst)
{
struct node *victim = *lst;
*lst = victim->nextPlane;
free(victim);
}
}
Invoked like this:
struct plane *lst = list_initialize(N);
// use list.., maybe adding nodes, removing them, changing, etc...
list_delete(&lst);
How to print your list:
void list_print(const struct plane *lst)
{
while (lst)
{
// TODO: print list node pointed to by lst.
// Ex: (x,y) coords
printf("(%d,%d) ",lst->xCord, lst->yCord);
lst = lst->nextPlane;
}
printf("\n");
}