function triangulation_plot ( input_node_filename, ...
  input_triangulation_filename, node_show, triangle_show )

%% TRIANGULATION_PLOT plots a triangulated set of nodes.
%
%  Discussion:
%
%    All arguments may be given on the command line.  Arguments may be omitted,
%    from right to left, in which case the program will prompt for the values.
%
%  Modified:
%
%    13 May 2005
%
%  Author:
%
%    John Burkardt
%
%  Usage:
%
%    triangulation_plot node_file tri_file triangle_show node_show
%
%  Parameters:
%
%    Input, character INPUT_NODE_FILENAME, the name of the node file.
%
%    Input, character INPUT_TRIANGULATION_FILENAME, the name of 
%    the triangulation file.
%
%    Input, integer NODE_SHOW, controls node visibility:
%    0, do not show nodes.
%    1, show nodes.
%    2, show and label nodes.
%
%    Input, integer TRIANGLE_SHOW, controls triangle visibility:
%    0, do not show triangles.
%    1, show triangles.
%    2, show and label triangles.
%
  fprintf ( 1, '\n' );
  timestamp;

  fprintf ( 1, '\n' );
  fprintf ( 1, 'TRIANGULATION_PLOT\n' );
  fprintf ( 1, '  MATLAB version\n' );
  fprintf ( 1, '\n' );
  fprintf ( 1, '  Read a node dataset of NODE_NUM points in 2 dimensions.\n' );
  fprintf ( 1, '  Read an associated triangulation dataset of TRI_NUM\n' );
  fprintf ( 1, '  triangles using 3 or 6 nodes.\n' );
  fprintf ( 1, '\n' );
  fprintf ( 1, '  Make an EPS plot of the triangulated data.\n' );
%
%  First argument is the node file.
%
  if ( nargin < 1 )
    fprintf ( 1, '\n' );
    fprintf ( 1, 'TRIANGULATION_PLOT:\n' );
    input_node_filename = input ( '  Enter the name of the node file.' );
  end
%
%  Second argument is the triangulation file.
%
  if ( nargin < 2 )
    fprintf ( 1, '\n' );
    fprintf ( 1, 'TRIANGULATION_PLOT:\n' );
    input_triangulation_filename = input ( ...
      '  Enter the name of the triangulation file.' );
  end
%
%  Third argument is node visibility.
%
  if ( nargin < 3 )
    fprintf ( 1, '\n' );
    fprintf ( 1, '  Options for node visibility:\n' );
    fprintf ( 1, '  0: do not show the nodes;\n' );
    fprintf ( 1, '  1:        show the nodes;\n' );
    fprintf ( 1, '  2:        show the nodes, and label them.\n' );
    node_show = input ( '  Enter the node visibility option:' );
  end
%
%  Fourth argument is triangle visibility.
%
  if ( nargin < 4 )
    fprintf ( 1, '\n' );
    fprintf ( 1, '  Options for triangle visibility:\n' );
    fprintf ( 1, '  0: do not show the triangles;\n' );
    fprintf ( 1, '  1:        show the triangles;\n' );
    fprintf ( 1, '  2:        show the triangles, and label them.\n' );
    triangle_show = input ( '  Enter the triangle visibility option:' );
  end
%
%  Create the output file name from the triangulation filename.
%
  output_filename = file_name_ext_swap ( input_triangulation_filename, 'eps' );

  [ dim_num, node_num ] = dtable_header_read (  input_node_filename );

  fprintf ( 1, '\n' );
  fprintf ( 1, '  Read the header of "%s".\n', input_node_filename );
  fprintf ( 1, '\n' );
  fprintf ( 1, '  Spatial dimension DIM_NUM = %d\n', dim_num );
  fprintf ( 1, '  Number of nodes NODE_NUM  = %d\n', node_num );

  node_xy = dtable_data_read ( input_node_filename, dim_num, node_num );

  fprintf ( 1, '\n' );
  fprintf ( 1, '  Read the data in "%s".\n', input_node_filename );

  r8mat_print_some ( dim_num, node_num, node_xy, 1, 1, 5, 5, ...
    '  5 by 5 portion of data read from file:' );
%
%  Read the triangulation data.
%
  [ tri_order, tri_num ] = itable_header_read (  input_triangulation_filename );

  fprintf ( 1, '\n' );
  fprintf ( 1, '  Read the header of "%d".\n', input_triangulation_filename );
  fprintf ( 1, '\n' );
  fprintf ( 1, '  Triangle order TRI_ORDER = %d\n', tri_order );
  fprintf ( 1, '  Number of triangles TRI_NUM  = %d\n', tri_num );

  triangle_node = itable_data_read ( input_triangulation_filename, ...
    tri_order, tri_num );

  fprintf ( 1, '\n' );
  fprintf ( 1, '  Read the data in "%s".\n', input_triangulation_filename );

  i4mat_print_some ( tri_order, tri_num, triangle_node, 1, 1, 5, 5, ...
    '  5 by 5 portion of data read from file:' );
%
%  Create the output file.
%
  if ( tri_order == 3 )

    triangulation_order3_plot ( output_filename, node_num, node_xy, ...
      tri_num, triangle_node, node_show, triangle_show );

  elseif ( tri_order == 6 )

    triangulation_order6_plot ( output_filename, node_num, node_xy, ...
      tri_num, triangle_node, node_show, triangle_show );

  end

  fprintf ( 1, '\n' );
  fprintf ( 1, '  Created the EPS file "%s".\n', output_filename );

  fprintf ( 1, '\n' );
  fprintf ( 1, 'TRIANGULATION_PLOT\n' );
  fprintf ( 1, '  Normal end of execution.\n' );

  fprintf ( 1, '\n' );
  timestamp;