public class CardTable
{
   // constructor methods

   public CardTable()
   {  ct = new PhoneCard[TABLE_LENGTH];
      ctSize = 0;
      current = 0;
   }

   // specialized methods

   public boolean add(PhoneCard card)
   {  if(ctSize == TABLE_LENGTH) return false;
      if(get(card.getNumber()) !=null) return false;
      ct[ctSize] = card;
      ctSize++;
      return true;
   }

   public PhoneCard get(long no)
   {  // YOU MUST FILL THIS PART
      // OF THE DEFINITION
   }

   public PhoneCard first()
   {  if(ctSize == 0)
      {  return null;
      }
      else
      {  current = 0;
         return ct[current];
      }
   }

   public PhoneCard next()
   {  if(current + 1 == ctSize)
      {  return null;
      }
      else
      {  current++;
         return ct[current];
      }
   }


   // instance variables/attributes/fields

   private PhoneCard[] ct;
   private int ctSize;
   private int current;

   // class/static variables/attributes/fields

    private static int TABLE_LENGTH = 20;   

}