1  public interface MySet<E> extends java.lang.Iterable<E> {
  2    /** Remove all elements from this set */
  3    public void clear();
  4    
  5    /** Return true if the element is in the set */
  6    public boolean contains(E e);
  7    
  8    /** Add an element to the set */
  9    public boolean add(E e);
 10  
 11    /** Remove the element from the set */
 12    public boolean remove(E e);
 13  
 14    /** Return true if the set contains no elements */
 15    public boolean isEmpty();
 16  
 17    /** Return the number of elements in the set */
 18    public int size();
 19  }