weekday

weekday, an Octave code which determines the day of the week corresponding to a given date; for instance, the battle of Hastings, on 14 October 1066 (Julian Calendar!), was a Saturday.

Licensing:

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

Languages:

weekday is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.

Related Data and Programs:

weekday_test

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

doomsday, an Octave code 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.

test_values, an Octave code which supplies test values of various mathematical functions.

Reference:

1. Lewis Carroll (Charles Dodgson),
   To Find the Day of the Week for Any Given Date,
   Nature,
   Volume 35, Number 909, 31 March 1887, page 517.
2. Gary Meisters,
   Lewis Carroll's Day-of-the-Week Algorithm,
   Math Horizons,
   November 2002, pages 24-25.
3. Edward Reingold, Nachum Dershowitz,
   Calendrical Calculations: The Millennium Edition,
   Cambridge University Press, 2001,
   ISBN: 0-521-77752-6,
   LC: CE12.R45.
4. Edward Richards,
   Mapping Time, The Calendar and Its History,
   Oxford, 1999,
   ISBN: 0-19-850413-6,
   LC: CE11.R5.

Source Code:

• i4_wrap.m forces an integer to lie between given limits by wrapping.
• jed_to_weekday.m computes the day of the week from a JED.
• jed_weekday_values.m returns weekday values for selected JED's.
• weekday_check_common.m, checks that a weekday specification is legal.
• weekday_to_name_common.m returns the name of a Common weekday.
• weekday_values.m returns the day of the week for various dates.
• y_common_to_astronomical.m converts a Common year to an Astronomical year.
• ymd_to_s_common.m writes a Common YMD date into a string.
• ymd_to_weekday_common.m returns the weekday of a Common YMD date.
• ymdf_compare.m compares two YMDF dates.
• ymdf_to_jed_common.m converts a Common YMDF date to a JED.
• ymdf_to_jed_gregorian.m converts a Gregorian YMDF date to a JED.
• ymdf_to_jed_julian.m converts a Julian YMDF date to a JED.