## 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} {} issquare (@var{x})
## Return true if @var{x} is a square matrix.
## @seealso{isscalar, isvector, ismatrix, size}
## @end deftypefn

## Author: A. S. Hodel <scotte@eng.auburn.edu>
## Created: August 1993
## Adapted-By: jwe

function retval = issquare (x)

  if (nargin != 1)
    print_usage ();
  endif

  if (ndims (x) == 2)
    [r, c] = size (x);
    retval = r == c;
  else
    retval = false;
  endif

endfunction


%!assert (issquare ([]))
%!assert (issquare (1))
%!assert (! issquare ([1, 2]))
%!assert (issquare ([1, 2; 3, 4]))
%!assert (! issquare ([1, 2; 3, 4; 5, 6]))
%!assert (! issquare (ones (3,3,3)))
%!assert (issquare ("t"))
%!assert (! issquare ("test"))
%!assert (issquare (["test"; "ing"; "1"; "2"]))
%!test
%! s.a = 1;
%! assert (issquare (s));
%!assert (issquare ({1, 2; 3, 4}))
%!assert (sparse (([1, 2; 3, 4])))

%% Test input validation
%!error issquare ()
%!error issquare ([1, 2; 3, 4], 2)