// date.h
// ----------------------------------------------------------------------
// declares class Date
// Do not modify this file.
// 
// CSE 143
// Homework 2, 3
// http://www.cs.washington.edu/education/courses/143/00su/homework/
// 25 Jun 2000; Man-Hing Wong, Ken Yasuhara

 
#ifndef _DATE_H_
#define _DATE_H_

class Date
{
public:

  // 
  // constructors, verification
  // 

  // creates a date that is invalid
  Date();  

  // allows construction of invalid dates
  Date(int newMonth, int newDay, int newYear); 

  // returns true iff 1 <= month <= 12, 
  // and 1 <= day <= max number of days in month, 
  // and year > 0
  bool isValid(); 


  // 
  // accessors
  // 

  // getYear() returns year in four-digit format
  int getMonth(); 
  int getDay(); 
  int getYear();                

  // 
  // methods
  // 

  // return a positive number if this date is earlier than otherDay;
  // return 0 if other is the same day;
  // return a negative number if this date is NOT earlier than otherDay;
  // (An invalid date comes before all valid ones, and on the same day
  // as all other invalid dates.)
  int compare(Date otherDay);

  // increment date by numDays days;
  // should yield invalid Date only by running off the end of the
  // year, e.g. 1/30 plus 3 days should yield the valid Date 2/2, not
  // the invalid 1/33
  // Precondition: 0 <= numDays
  void addDays(int numDays); 

  // return how many days (absolute value) between this date and given date
  int dayDifference(Date d); 

  // print this date
  void printDate();

  // return number of days in given month of given year,
        // taking leap years into account;
  // mostly used internally, e.g. by addDays()
  int daysInMonth(int month, int year);


private:

  // 
  // member data
  // 
  
  int month;
  int day;
  int year;
};


#endif