import java.util.*;

public class MyTestHashMap
{
   public static void main(String[] args) 
   {
      int i;
      Integer freq;
      String s;

      Map<String, Integer> M = new HashMap<String, Integer>(4);

      M.put("a", 1);
      System.out.println(M);
      M.put("b", 1);
      System.out.println(M);
      M.put("c", 1);
      System.out.println(M);
      M.put("d", 1);
      System.out.println(M);
      M.put("e", 1);
      System.out.println(M);

      M.remove("a");
      System.out.println(M);
      M.remove("b");
      System.out.println(M);
      M.put("e", 1);
      System.out.println(M);

      System.out.println("\nAll the keys: ");

      Collection<String> c = M.keySet();

       /* ------------------------------------------------
          Get an iterator over a Set
          ----------------------------------------------- */
       Iterator iter = c.iterator();

       /* -------------------------
          Iterate over "iter"
         ------------------------- */
       while(iter.hasNext())
       {
          String x;    // Help variable
 
          x = (String) iter.next();              // Get next entry      

          System.out.print(x + " ");
       }
       System.out.println();

      /* ================================================= */

      System.out.println("\nAll the entries: ");

      Collection<Entry<String,Integer>> c2 = M.entrySet();

       /* ------------------------------------------------
          Get an iterator over a Set
          ----------------------------------------------- */
       Iterator iter2 = c2.iterator();

       /* -------------------------
          Iterate over "iter"
         ------------------------- */
       while(iter2.hasNext())
       {
          Entry<String,Integer> x;    // Help variable

          x = (Entry<String,Integer>) iter2.next();     // Get next entry

          System.out.print(x + " ");
       }
       System.out.println();



   }
}