DOOMSDAY
Day of Week for Given Date

DOOMSDAY is a MATLAB library which is given the year, month and day of a date, and uses John Conway's doomsday algorithm to determine the corresponding day of the week.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

DOOMSDAY is available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version.

Related Data and Programs:

CALENDAR_NYT, a MATLAB library which shows the correspondence between dates and the New York Times volume and issue number;

CALENDAR_RD, a C++ program which computes the representation of a given date in a number of calendrical systems, by Edward Reingold and Nachum Dershowitz

CALPAK, a FORTRAN90 library which makes various calendar calculations;

DATES, a dataset directory which contains lists of dates in various calendar systems.

WEEKDAY, a MATLAB library which determines the day of the week for a given day.

Reference:

1. Lewis Carroll (Charles Dodgson),
   To Find the Day of the Week for Any Given Date,
   Nature, 31 March 1887.
2. John Conway,
   Tomorrow is the Day After Doomsday,
   Eureka,
   Volume 36, October 1973, pages 28-31.
3. Gary Meisters,
   Lewis Carroll's Day-of-the-Week Algorithm,
   Math Horizons,
   November 2002, pages 24-25.

Source Code:

• doomsday_gregorian.m, weekday given any date in Gregorian calendar.
• i4_modp.m, returns the nonnegative remainder of I4 division.
• i4_wrap.m, forces an I4 to lie between given limits by wrapping.
• timestamp.m, prints the current YMDHMS date as a time stamp.
• weekday_to_name_common.m, returns the name of a Common weekday.
• weekday_values.m, returns the day of the week for various dates.
• year_is_leap_gregorian.m, returns TRUE if the Gregorian year was a leap year.

Examples and Tests:

• doomsday_test.m, calls all the tests.
• doomsday_test01.m, checks a couple simple dates.
• doomsday_test02.m, checks a list of dates.
• doomsday_test_output.txt, the output file.

You can go up one level to the MATLAB source codes.