Julian Julian/Gregorian date class

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Description

	The Julian class encapsulates and manipulates dates as Julian integers. Julian integers represent the day since the first day of Gregorian year zero. Julian dates are stored as long integers, making date arithmetic as easy as addition and subtraction.
	Methods are provided for determining the current system date, and for converting Julian date integers to and from their Gregorian day/month/year counterparts, as well as producing RFC 822-formatted text representations.
	This class is intended for use with the htmlCookie class to compute expiration dates for cookies, but is general-purpose in nature and suitable for other tasks as well.

Declaration

	#include <dcmicro/htmlpp/julian.h>

Hierarchy
See Also

	htmlCookie

Related Constants/Definitions

	None.

Constructors

	Julian()

	Constructs a Julian date object, setting the value to today's date.

	Julian( long julian_date )

	Constructs a Julian date object, setting the value to julian_date.

Destructors

	virtual ~Julian()

	Destroys the object.

Member Methods

	JulianDate	long JulianDate()

	Returns the date value of the object as a Julian integer.

	Today	long Today()

	Returns the current system date as a Julian integer.

	MDY	long MDY( short month, short day, short year )

	Converts Gregorian month (1-12), day (1-31), and year (0-9999) values to a Julian integer.

	MDY	void MDY( long julian_date,
		short FAR * month,
		short FAR * day,
		short FAR * year )

	Converts julian_date to Gregorian month (1-12), day (1-31), and year (0-9999) values. If NULL is supplied for month, day, or year, the values will not be populated.

	Day	short Day( long julian_date = JULIAN_DEFAULT )

	Returns the Gregorian day of the month (1-31) for the specified julian_date. If no argument is supplied, the date value of the object will be used by default.

	Month	short Month( long julian_date = JULIAN_DEFAULT )

	Returns the Gregorian month (1-12) for the specified julian_date. If no argument is supplied, the date value of the object will be used by default.

	Year	short Year( long julian_date = JULIAN_DEFAULT )

	Returns the Gregorian year for the specified julian_date. If no argument is supplied, the date value of the object will be used by default.

	DayOfWeek	short DayOfWeek( long julian_date = JULIAN_DEFAULT )

	Returns the day of the week (0=Sunday, 1=Monday, ..., 6=Saturday) for the specified julian_date. If no argument is supplied, the date value of the object will be used by default.

	RFC822	String RFC822( long julian_date = JULIAN_DEFAULT )

	Returns an RFC 822-formatted text string representing the date specified by julian_date. A time of 12pm GMT is assumed. RFC 822 is an internet protocol document that specifies that dates should be of the form:
	Weekday, dd-Mon-yyyy hh:mm:ss GMT
	This method is intended for use with the htmlCookie::Expires() method. If no argument is supplied, the date value of the object will be used by default.

	=	Julian& operator= ( long julian_date )

	Assigns the value of the object to julian_date, and returns a reference to the object.

	+=	long operator += ( long days )

	Adds days to the julian date value of the object.

	-=	long operator -= ( long days )

	Subtracts days from the julian date value of the object.

	(long)	operator long ( void )

	Casts the julian date value of the object as a long integer.

	Print	/* virtual */ void Print( ostream& os ) const

	Outputs the object to os.

Example Use

	#include <stdio.h>
	#include <stdlib.h>
	#include <dcmicro/htmlpp/htmlpp.h>
	int main( void )
	{
	htmlCgi   server ;
	htmlPage  page( "html++ example application" ) ;
	//  Create a new cookie for the page
	htmlCookie   cookie ;
	cookie.Domain( ".yourdomain.com" )
	.Path( "/" ) ;
	Julian j ;  //  today's date
	j += 30 ;   //  add thirty days
	cookie.Expires( j.RFC822() ) ;
	//  Set the customer id as the cookie value
	cookie.Value( "customerid", "1234" ) ;
	page << cookie ;
	server << page ;
	return 0 ;
	}

Program Output

	Content-Type: text/html
	Set-Cookie: customerid=1234; expires=Wednesday, 31-Dec-1997 12:00:00 GMT; path=/; domain=.yourdomain.com
	<HTML>
	<HEAD>
	<TITLE>html++ example application</TITLE>
	</HEAD>
	<BODY>
	</BODY>
	</HTML>

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