function price_line_plots ( )

%*****************************************************************************80
%
%% price_line_plots reads price data and plots 3 prices on one display.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    08 October 2019
%
%  Author:
%
%    John Burkardt
%
  fprintf ( 1, '\n' );
  fprintf ( 1, 'price_line_plots:\n' );
  fprintf ( 1, '  MATLAB version\n' );
  fprintf ( 1, '  Plot prices of bananas, gas and milk over time.\n' );
%
%  Read the (241) items of data.
%
  data = load ( 'price_data.txt' );
  bananas = data(:,3);
  gas = data(:,10);
  milk = data(:,13);
%
%  Create a vector MONTH, simply counting months from 1 to 241.
%
  month = linspace ( 1, 241, 241 );
%
%  Plot 3 (X,Y) curves together.
%
  plot ( month, bananas, month, gas, month, milk, 'linewidth', 3 );
  legend ( 'Bananas', 'Gas', 'Milk' );
  grid ( 'on' )
  xlabel ( 'Month Index', 'fontsize', 16 );
  ylabel ( 'Price in Dollars', 'fontsize', 16 );
  title ( 'Prices, Feb 2008-Feb 2018', 'fontsize', 16 );
%
%  Save the graphics in a file.
%
  filename = 'price_line_plots.png';
  print ( '-dpng', filename );
  fprintf ( 1, '\n' );
  fprintf ( 1, '  Graphic data saved in "%s"\n', filename );
%
%  Terminate.
%
  fprintf ( 1, '\n' );
  fprintf ( 1, 'price_line_plots:\n' );
  fprintf ( 1, '  Normal end of execution.\n' );

  return
end

