function ch_is_digit_test ( )

%*****************************************************************************80
%
%% ch_is_digit_test() tests ch_is_digit().
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    08 September 2015
%
%  Author:
%
%    John Burkardt
%
  c_test = [ ...
    '0', '1', '2', '3', '4', ...
    '5', '6', '7', '8', '9', ...
    'X', '?', ' ' ];

  fprintf ( 1, '\n' );
  fprintf ( 1, 'ch_is_digit_test():\n' );
  fprintf ( 1, '  ch_is_digit() is TRUE if a character represents a digit.\n' );
  fprintf ( 1, '\n' );
  fprintf ( 1, '   C      CH_IS_DIGIT(C)\n' );
  fprintf ( 1, '\n' );

  for i = 1 : 13
    c = c_test(i);
    value = ch_is_digit ( c );
    fprintf ( 1, '  "%c"            %d\n', c, value );
  end

  return
end
