///////    CirbufItr.java    ///////
import java.util.Enumeration;

class CirbufItr extends Cirbuf
{ 
    public CirbufItr() { super(SIZE); }   // no-arg constructor
    public CirbufItr(int s)
    {    super(s);   }

    public Enumeration elements()
    {   return (new Iterator(head, tail));  }

    private final class Iterator implements Enumeration
    {   public Iterator(int h, int t)
        { i0 = h;  i1 = t; }

        public Object nextElement()
        {   if ( i0 == i1 ) return null;
            Character c =  new Character(cb[i0++]);
            i0 = mod(i0);
            return c;
        }
        public boolean hasMoreElements()
        {   return ( i0 != i1);  }
        private int i0, i1;   // head, tail indices
    }
}