import java.util.TreeSet;
public class SetDemo
{
  public static void main(String[] args)
  {
     //Demo Tree Set 
     TreeSet<String> ts = new TreeSet<String> (  ) ; 
  
     System.out.println ( ts.isEmpty (  )  ) ; 
     ts.add ( "Chicago" ) ; 
     ts.add ( "Mumbai" ) ; 
     ts.add ( "Delhi" ) ; 
     ts.add ( "NY" ) ; 
     ts.add ( "Chicago" ) ;
      
     for (String item: ts)
     {
       System.out.println ( "city: " + item ) ; 
     } 
      
     //Experimenting with some basic operations 
     System.out.println ( ts.isEmpty (  )  ) ; 
     System.out.println ( ts.size (  )  ) ; 
     System.out.println ( "Does it contain Delhi "+ts.contains ( "Delhi" )  ) ; 
     System.out.println ( "Adding Paris "+ts.add ( "Paris" )  ) ; 
     System.out.println ( "have you removed NY " + ts.remove ( "NY" )  ) ; 
      
     //Experimenting with some bulk operations 
     TreeSet<String> coll = new TreeSet<String> (  ) ; 
     coll.add ( "SLO" ) ; 
     coll.add ( "NY" ) ; 
     System.out.println ( "Does it contain ny, SLO "+ts.containsAll ( coll )  ) ; 
     System.out.println ( "Has it added ny, SLO "+ts.addAll ( coll )  ) ; 
     System.out.println ( "have you removed NY " + ts.remove ( "NY" )  ) ; 
      
     for (String item: ts)
     {
       System.out.println ( "city: " + item ) ; 
     } 
      
  
  } 
}

/* OUTPUT
true
city: Chicago
city: Delhi
city: Mumbai
city: NY
false
4
Does it contain Delhi true
Adding Paris true
have you removed NY true
Does it contain ny, SLO false
Has it added ny, SLO true
have you removed NY true
city: Chicago
city: Delhi
city: Mumbai
city: Paris
city: SLO
*/