more work on linked list

c/linked_list.c

@@ -80,6 +80,17 @@ void insert_at(LinkedList* list, Node* node, int index) {
     }
 }
 
+void remove_at_end(LinkedList* list) {
+    if (list->length == 0) {
+        printf("ERROR: cannot remove from an empty list\n");
+    } else {
+        Node* node_to_remove = list->tail;
+        list->tail = node_to_remove->prev;
+        list->tail->next = NULL;
+        free(node_to_remove);
+    }
+}
+
 int get_length(LinkedList* list) {
     return (list->length);
 }
@@ -109,25 +120,69 @@ void print_list(LinkedList* list) {
     printf("] <length: %d>\n", get_length(list));
 }
 
+LinkedList* new_list_from_array(int arr[], int length) {
+    if (length == 0) {
+        printf("ERROR: i mean c'mon");
+    }
+    LinkedList* list = new_linked_list();
+    Node*       n = new_node(arr[1]);
+    list->head = n;
+    list->length++;
+    for (int i = 1; i < length; i++) {
+        Node* n = new_node(arr[i]);
+        append(list, n);
+    }
+
+    return (list);
+}
+
 int main() {
     LinkedList* list = new_linked_list();
-    Node*       a = new_node(10);
+
-    Node*       b = new_node(11);
+    Node* a = new_node(10);
+    Node* b = new_node(11);
     preppend(list, a);
+    print_list(list);
     preppend(list, b);
+    print_list(list);
     preppend(list, new_node(12));
+    print_list(list);
     preppend(list, new_node(13));
+    print_list(list);
     preppend(list, new_node(14));
+    print_list(list);
     preppend(list, new_node(15));
+    print_list(list);
 
     append(list, new_node(100));
-    append(list, new_node(200));
-
     print_list(list);
+    append(list, new_node(200));
+    print_list(list);
+
     insert_at(list, new_node(-1), 0);
+    print_list(list);
     insert_at(list, new_node(-1), 4);
     print_list(list);
 
+    remove_at_end(list);
+    print_list(list);
+    remove_at_end(list);
+    print_list(list);
+    remove_at_end(list);
+    print_list(list);
+    remove_at_end(list);
+    print_list(list);
+    remove_at_end(list);
+    print_list(list);
+    remove_at_end(list);
+    print_list(list);
+    remove_at_end(list);
+    print_list(list);
+    remove_at_end(list);
+    print_list(list);
+
+    int first_node_val = get_val(list, 1);
+    printf("the value at the first node is: %d\n", first_node_val);
     destroy_list(list);
 
     return (0);