update packages

[CreaPhase.git] / octave_packages / m / time / is_leap_year.m

diff --git a/octave_packages/m/time/is_leap_year.m b/octave_packages/m/time/is_leap_year.m
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+## Copyright (C) 1996-2012 John W. Eaton
+##
+## This file is part of Octave.
+##
+## Octave is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## Octave is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {} is_leap_year ()
+## @deftypefnx {Function File} {} is_leap_year (@var{year})
+## Return true if @var{year} is a leap year and false otherwise.  If no
+## year is specified, @code{is_leap_year} uses the current year.
+## For example:
+##
+## @example
+## @group
+## is_leap_year (2000)
+##    @result{} 1
+## @end group
+## @end example
+## @seealso{weekday, eomday, calendar}
+## @end deftypefn
+
+## Author: jwe
+
+function retval = is_leap_year (year)
+
+  if (nargin > 1)
+    print_usage ();
+  endif
+
+  if (nargin == 0)
+    t = clock ();
+    year = t(1);
+  endif
+
+  retval = (rem (year, 4) == 0 & rem (year, 100) != 0) | (rem (year, 400) == 0);
+
+endfunction
+
+
+%!assert (is_leap_year (2000), true)
+%!assert (is_leap_year (1976), true)
+%!assert (is_leap_year (1000), false)
+%!assert (is_leap_year (1800), false)
+%!assert (is_leap_year (1600), true)
+
+%!error is_leap_year (1, 2);
+