#include <stdio.h>
#include <stdlib.h>


/*TODO:
 *  account for indexes greater than list size
 */


typedef struct linkedlist {
    int data;
    struct linkedlist *next;
} LinkedList_t;

LinkedList_t *createLinkedList(int d)
{
    LinkedList_t *p = malloc(sizeof(LinkedList_t));
    p->data = d;
    p->next = NULL;

    return p;
}

int push(LinkedList_t *h, int d)
{
    // Add to the top of the list
    if(h == NULL)
        return -1;

    LinkedList_t *k = h;
    while(k->next != NULL) {
        k = k->next;
    }
    k->next = createLinkedList(d);
    return 0;
}

int pop(LinkedList_t *h)
{
    // Delete last entry
    if(h == NULL)
        return -1;

    if(h->next == NULL)
        free(h);

    // get to second to last entry, then free
    LinkedList_t *k = h;
    while(k->next->next != NULL) {
        k = k->next;
    }
    free(k->next);
    k->next = NULL;
    return 0;
}

int search(LinkedList_t *h, int st)
{
    LinkedList_t *k = h;
    int i = 0;
    while(k->data != st) {
        k = k->next;
        i++;
    }

    return i;
}

int deleteByIndex(LinkedList_t *h, int index)
{
    LinkedList_t *k = h;
    if(index == 0) {
        k = k->next;
        *h = *k;
        return 0;
    }

    for(int i = 0; i < index - 1; i++) {
        k = k->next;
    }

    free(k->next);

    k->next = k->next->next;
    return 0;
}

void setDataByIndex(LinkedList_t *h, int index, int s)
{
    LinkedList_t *k = h;
    for(int i = 0; i < index; i++) {
        k = k->next;
    }

    k->data = s;
}

int getDataByIndex(LinkedList_t *h, int index)
{
    LinkedList_t *k = h;
    for(int i = 0; i < index; i++) {
        k = k->next;
    }

    return k->data;
}

void printList(LinkedList_t *h)
{
    LinkedList_t *t = h;
    while(t != NULL) {
        printf("%d\n", t->data);
        t = t->next;
    }
}

int main()
{
    LinkedList_t *head = createLinkedList(1);
    push(head, 2);
    push(head, 3);
    push(head, 4);

    printList(head);
    puts("");
    setDataByIndex(head, 1, 10);
    printList(head);
    return 0;
}