public class LinkedList<T> implements ListInterface<T> {

   Node<T> head;
   int size;
   // constructor
   public class Node<T> {
      public T data;
      public Node<T> next;
      public Node (T data, Node<T> next) {
         this.data = data;
         this.next = next;
      }
   }
   //add
   public void add(T data, int index) {
      if (size == 0 || index == 0) { // if there isn't an existing list create one and set head position
         head = new Node<T>(data, head);
      }
      else { // loops the list starting from head, at an empty spot add the object
         Node<T> current = head;
         while(index > 1) {  // increment pointer until desired index is reached
            current = current.next;
            index--;
         }
         current.next = new Node<T>(data, current.next);
      }
      size++;
   }
   // get
   public T get(int index) {
      Node<T> current = head;
      while(index > 0) {
         if (current == null) {  // if nothing exists at this index, throw exception
            throw new ListException("Cannot get item/DNE.");
         }
         // increment pointer
         current = current.next;
         index--;
      }
      return current.data;
   }
   // remove
   public void remove(int index) {
      Node<T> current = head;
      if (current == null)// if there isn't an object in the index, throw exception
         throw new ListException("Cannot remove item/DNE.");
      if(index == 0) { // If you want to remove at the beginning, we need to reassign the head
         head = head.next;
      }
      else {
         while (index > 1) { // loop to the desired index
            current = current.next;
            index--;
         }
         // reassigns the index, removed item is detached and gets garbage collected.
         current.next = current.next.next;
      }
      size--;
   }
   // size
   public int size() {
      return size;
   }
   // Appends contents of list to a stringbuffer and returns them
   public String toString() {
      Node<T> node = head;
      StringBuffer str = new StringBuffer();
      while (node != null) {
         str.append(node.data.toString() + " ");
         node = node.next;
      }
      return str.toString();
   }
}