public class go { 
   example  
  
  public static void main(String[] args) {
  	person p = new person(); p.talk(); 
 empty
  	p.become(actor.Student); p.talk(); 
 OOP
  	p.become(actor.Employer); p.talk(); 
 money
  	p.become(new adult()); p.talk(); 
 interesting
  	p.become(actor.Student); p.talk(); 
 OOP
  	p.become(p); p.talk(); 
 old role: employer
  	p.become(actor.Person); p.talk(); // initial state
  	}
  };