public interface ListInterface
{
    // makes the list contain no items
    public void clear();

    // add item at start of list
    // generates a FullListException if list is full
    public void add (int item);
    
//     // add item at given position
//     // generates an IllegalPositionException if position is invalid
//     public void add (Object item, int position);
//     
//     // remove the item that exists at the given position
//     // generates an IllegalPositionException if position is invalid
//     public void remove (int position);
//     
//     // remove first occurrence of item in the list
//     // if item does not exist, do nothing
//     public void remove (Object item);
//     
//     // remove all occurrences of item in list
//     // if item does not exist, do nothing
//     public void removeAll (Object item);
//     
//     // returns the item at the given position
//     // generates an IllegalPositionException if position is invalid
//     public Object viewItem(int position);
//     
//     // place the list into ascending order
//     public void sort();
//     
    // print all items in the list
    public String toString();
    public void print();
    
//     // return the number of items in the list
//     public int size ();

}