import java.text.DecimalFormat;

/* TimeOfDay12Or24.java
** An instance of this class represents an immutable time of day, precise to
** a minute.  It extends its parent class by supporting not only a 24-hour mode
** (as is supported by the parent class) but also an AM/PM mode (which this
** class introduces).  Essentially, the new capability that this class provides
** is that its toString() method produces a string that describes the time of
** day either in 12-hour mode (e.g., "7:46AM", "8:19PM") or in 24-hour mode
** (e.g., "07:46", "20:19"), according to the current mode of the object.
** Mutator methods allow the client to set the mode as desired.
**
** Authors: R. McCloskey and < STUDENTS' NAMES >
** Flaws: ...
**
*/
public class TimeOfDay12Or24 extends TimeOfDay {

   // instance variable
   // -----------------

   private boolean in24Mode;   // true means 24-hour mode is in force; 
                               // false means 12-hour mode is in force

   // constructor
   // -----------

   /* Initializes this time of day to the specified hour and minute, the hour
   ** value assumed to be expressed in accord with 24-hour mode.
   ** The object's initial mode is 24-hour.
   */
   public TimeOfDay12Or24(int hr, int min) {
      super(hr, min);     // call parent class's constructor
      setToMode24();      // sets the mode to 24-hour mode
   }


   // observers
   // ---------

   /* Reports whether or not this object is in 24-hour mode.
   */
   public boolean in24HourMode() { return in24Mode; }

   /* Reports whether or not this object is in 12-hour mode.
   */
   public boolean in12HourMode() { return !in24Mode; }

   /* Returns a string describing the time of day represented by this object,
   ** where the form of the string is consistent with the object's current
   ** mode.  For example, when in 24-hour format, the string produced
   ** could be "08:15".  When in 12-hour format, it would be "8:15AM".
   */
   @Override
   public String toString() {
      DecimalFormat hourFormatter = new DecimalFormat("#0");
      DecimalFormat minuteFormatter = new DecimalFormat("00");

      // *** Missing code ***

      return "";   // STUB!
   }


   // mutators
   // --------

   /* Sets this object's mode to 24-hour mode.
   */
   public void setToMode24() { in24Mode = true; }

   /* Sets this object's mode to 12-hour mode.
   */
   public void setToMode12() { in24Mode = false; }


   // private methods
   // ---------------

   /* Given a 24-hour mode hour value, returns either "AM" or "PM" according
   ** to whether, respectively, the indicated hour value occurs in the AM
   ** or the PM.
   */
   private String hourToAMorPM(int hr) {
      return "";  // STUB
   }

   /* Given a 24-hour mode hour value, returns the corresponding hour value
   ** in 12-hour mode.  For example, hour 0 translates into hour 12 (as in 
   ** 12AM), and hour 19 translates to hour 7 (as in 7PM).
   */
   private int hour24To12(int hr) {
      return 0;     // STUB
   }

}