//
// dateclass2.cpp
//
// This file contains the definition of a date 
// class that is more realistic than the one in
// dateclass1.cpp.
//

#include <iostream.h>

class date {

private:
  int month;
  int day;
  int year;
  
  int isLeapYear(int year);
  int daysInMonth(int month, int year);
  int legalDate(int checkMonth, int checkDay, int checkYear);

public:
  date();
  ~date();
  int getDay();
  int getMonth();
  int getYear();
  int set(int newMonth, int newDay, int newYear);
  void print();
  int JulianDay();
};


//
// This is the definition of the constructor function.
//
date::date()
{
  month = 0;
  day = 0;
  year = 0;
}

//
// This is the definition of the destructor function.
//
date::~date()
{
}

//
// These are the definitions of the three accessor
// functions.
//
int date::getDay()
{
  return day;
}

int date::getMonth()
{
  return month;
}

int date::getYear()
{
  return year;
}

//
// isLeapYear returns true if the year passed
// to it is a leap year (according to the
// Gregorian calendar).
//
int date::isLeapYear(int year)
{
  if ((year % 4) == 0) {
  	if ((year % 400) == 0) {
      return 0;
  	}
  	else {
  	  return 1;
  	}
  }
  else {
    return 0;
  }
}

// daysInMonth expects month to be in the 
// range 1 to 12.  It returns the number of
// days in that month.  It knows how to 
// handle February in leap years correctly.
//
int date::daysInMonth(int month, int year)
{
  if (month < 1 || month > 12) {
  	return 0;
  }
  
  if (month == 1 || month == 3 ||
      month == 5 || month == 7 ||
      month == 8 || month == 10 ||
      month == 12) {
    return 31;
  }
  else if (month == 4 || month == 6 ||
           month == 9 || month == 11) {
    return 30;
  }
  else if (month == 2 && isLeapYear(year)) {
  	return 29;
  }
  else {
  	return 28;
  }
}

//
// legalDate returns true if the date is correct.  
//
int date::legalDate(int checkMonth, int checkDay, int checkYear)
{
  if (checkMonth < 1 || checkMonth > 12) {
  	return 0;
  }
  
  if (checkDay > daysInMonth(checkMonth, checkYear)) {
  	return 0;
  }

  return 1;
}

//
// set sets the date object to the month, day,
// and year passed as parameters if it's a 
// legal date.  Otherwise, it leaves the date
// unchanged.  It returns true if the date was
// changed and false otherwise.
//
int date::set(int newMonth, int newDay, int newYear)
{
  if (legalDate(newMonth, newDay, newYear)) {
    month = newMonth;
    day = newDay;
    year = newYear;
    return 1;
  }
  return 0;
}

//
// print prints a date in the usual month/day/year
// form.
//
void date::print()
{
  cout << month << "/" << day << "/" << year;
  return;
}

//
// JulianDay returns the number of the date's
// day in the year.
//
int date::JulianDay()
{
  int index;
  int dayCount = 0;
  
  for (index = 1; index < month; index++) {
    dayCount += daysInMonth(index, year);
  }
  dayCount += day;
  return dayCount;
}