WEEKDAY
Determine the Day of the Week


WEEKDAY is a FORTRAN90 library which can determine 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 GNU LGPL license.

Languages:

WEEKDAY 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:

ANALEMMA, a FORTRAN90 program which evaluates the equation of time, a formula for the difference between the uniform 24 hour day and the actual position of the sun, based on a program by Brian Tung.

CALENDAR_NYT, a FORTRAN90 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, Nachum Dershowitz

CALPAK, a FORTRAN90 library which makes various calendar calculations;

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

DOOMSDAY, a FORTRAN90 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.

TEST_VALUES, a FORTRAN90 library 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, 31 March 1887.
  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:

Examples and Tests:

List of Routines:

You can go up one level to the FORTRAN90 source codes.


Last revised on 25 March 2010.