/* This file defines a class for storing dates.
 * 
 * Warning: The methods of this class access the private
 * data directly. Java style gurus frown on this.
 * Private data members should be accessed exclusively
 * through accessor and mutator methods.
 */

public class Date {
	private int month;		// the month (from 1-12)
	private int day;		// the day of the month
	private int year;		// the year (four digits)
	
	/* Constructor method initializes a new Date object */
	public Date( int m, int d, int y ) {
		month = m;  day = d;  year = y;
		/* This has been added */
		if ( d < 1 || d > lastDayOfMonth( m, y) )
			System.out.println( "Warning: day is out of range" );
	}

	/* Converts to a string (US style: MM/DD/YYYY) */
	public String toString( ) {
		return new String( month + "/" + day + "/" + year );
	}
	
	/* Is this date equal to another? */
	public boolean equals( Date d ) {
		if ( ( year == d.year ) && ( month == d.month ) && ( day == d.day ) )
			return true;
		else
			return false;
	}
	
	/* ----------- This material was added later -------------*/
	
	static public final int DAYS_PER_WEEK = 7;
	static public final int MONTHS_PER_YEAR = 12;
	
	/* Is the given year a leap year? */
	public static boolean isLeapYear( int yr ) {
		boolean answer;
		if      ( (yr % 400) == 0 ) answer = true;	// multiple of 400
		else if ( (yr % 100) == 0 ) answer = false;	// multiple of 100
		else if ( (yr %   4) == 0 ) answer = true;	// multiple of 4
		else                        answer = false;	// not a multiple of 4
		return answer;
	}
	
	/* Given a month and year, returns the last day of this month. */
	private static int lastDayOfMonth( int mo , int yr) {
		int nDays;
		if ( mo == 4 || mo == 6 || mo == 9 ||	mo == 11 )
			nDays = 30;
		else if ( mo == 2) {
			if (isLeapYear( yr ) ) nDays = 29;
			else nDays = 28;
		} else {
			nDays = 31;
		}
		return nDays;
	}

}