Question

Im trying to create a linked list in c. The twist is that I want to allocate the memory for the list so that all the nodes are consecutively stored in memory.
Maybe an array structure is the way to go.
Any ideas?

Answer 1

The obvious way would be to allocate a number of nodes in a block, then link them together into a free list. When you need to add a node to your linked list, you’ll grab the one from the head of your free list. When you want to delete a node, you link it back onto the free list:

struct node { 
     struct node *next;
     // other data here.
};

node *free_list;

#define block_size 1024

void initialize() {
    free_list = malloc(block_size * sizeof(struct node));

    for (i=0; i<block_size-1; i++)
        free_list[i].next = &free_list[i+1];
    free_list[block_size-1].next = NULL;
}

struct node *alloc_node() { 
    struct node *ret;
    if (free_list == NULL)
        return NULL;
    ret = free_list;
    free_list = free_list->next;
    return ret;
}

void free_node(struct node *n) { 
    n->next = free_list;
    free_list = n;
}