function r8_cos_test ( )

%*****************************************************************************80
%
%% R8_COS_TEST tests R8_COS.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    23 April 2016
%
%  Author:
%
%    John Burkardt
%
  addpath ( '../test_values' );

  fprintf ( 1, '\n' );
  fprintf ( 1, 'R8_COS_TEST:\n' );
  fprintf ( 1, '  R8_COS evaluates the cosine function.\n' );
  fprintf ( 1, '\n' );
  fprintf ( 1, '             X         COS(X)  R8_COS(X)         Diff\n' );
  fprintf ( 1, '\n' );

  n_data = 0;

  while ( 1 )

    [ n_data, x, fx1 ] = cos_values ( n_data );

    if ( n_data == 0 )
      break
    end

    fx2 = r8_cos ( x );

    fprintf ( 1, '  %14.4f  %14.6g  %14.6g  %14.6g\n', x, fx1, fx2, abs ( fx1 - fx2 ) );

  end

  rmpath ( '../test_values' );

  return
end
