/* An instance of this class represents a calendar date.
**
** Author: R. McCloskey
** Date: Feb. 2026
*/


public class CalendarDate {

   // class constant
   // --------------

   public static final int MIN_YEAR = 1583; // First full year in which the
                                            // Gregorian calendar was in effect
   public static final int MAX_MONTH = 12;

   // instance variables
   // ------------------

   protected int month;
   protected int dayOfMonth;
   protected int year;

   // class invariant: 1 <= month <= MAX_MONTH
   // class invariant: 1 <= dayOfMonth <= daysInMonth(month, year)
 

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

   /* Initializes this calendar date to represent the date described by
   ** the three parameters.
   ** pre: 1 <= m <= MAX_MONTH  &&  
   **      1 <= d <= daysInMonth(y,m) && 
   **      MIN_YEAR <= y
   */
   public CalendarDate(int m, int d, int y) {
      this.month = m;  this.dayOfMonth = d; this.year = y;
   }


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

   @Override
   /* Returns a string describing this calendar date in the M/D/Y format.
   */
   public String toString() {
      return String.format("%02d/%02d/%04d", month, dayOfMonth, year);
   }

   // mutators (none)
   // ---------------


   // utility methods
   // ---------------

   /* Reports whether or not the specified year is a leap year.
   */
   public boolean isLeapYear(int y) {
      return (y % 400 == 0) || (y % 4 == 0  &&  y % 100 != 0);
   }

   /* Returns the number of days in the specified month of the specified
   ** year.
   ** pre: 1 <= m <= MAX_MONTH  &&  MIN_YEAR <= y
   */
   public int daysInMonth(int m, int y) {
      int[] days = new int[] { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
      if (m != 2) { return days[m-1]; }
      else if (isLeapYear(y)) { return days[1] + 1; }
      else { return days[1]; }
   }
   
}