public class MyLinkedList<E> implements MyList<E> {
  private Node<E> head;
  private int size;

  public MyLinkedList() {
    head = null;
    size = 0;
  }

  // appends elem to the end
  public void add( E elem ) {
  }

  public void add( int index, E elem ) {		
  }

  // replaces the element at index with elem
  // returns the element previously at index
  public E set(int index, E elem) {
    return null;
  }
	
  // returns the element at index
  public E get(int index) {
    return null;
  }

  // removes first occurrence of elem if found, 
  // shift subsequent elemenets up, and return true,
  // else return false and no changes are made
  public boolean remove( E elem ) {
    return false;
  }
	
  public E remove(int index) {
    return null;
  }

  public void clear() {		
  }
	
  // returns the index of the first occurrence of elem
  // or -1 if elem not found
  public int indexOf(E elem) {
    return 0;
  }
	
  public int lastIndexOf(E elem) {
    return 0;
  }

  // returns true if this list contains elem, false otherwise
  public boolean contains(E elem) {
    return false;
  }

  public boolean isEmpty() {
    return false;
  }

  // returns the number of elements in list
  public int size() {
    return 0;
  }

  public String toString() {
    String str = "";
    Node<E> current = head;
    while (current != null) {
      str += current.element;
      // check if end of list
      if( current.next != null ) 
        str += " ";
      // advance to next node
      current = current.next;
    }
    return str;
  }
 }