Values of each expression
  String s1 = new String(“today”);
  String s2 = new String(“yesterday”);
  String s3 = new String(“today”);
  String s4 = new String(“Today”);
  s1.compareTo(s2)         -5
  s1 == s3           false
  s1.compareTo(s3)         0
  s1.compareTo(s4)          32