function histogram_display ( input_file_name )

%% HISTOGRAM_DISPLAY makes a stacked bar plot of a set of histogrammed data.
%
%  Discussion:
%
%    The input data is a single file, whose first column is taken as a set of
%    average X values.
%
%    Each subsequent column is taken as the corresponding Y coordinates of
%    a histogram.  All the columns are plotted together as a stacked bar plot.
%
%  Modified:
%
%    08 November 2005
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, string INPUT_FILE_NAME, the name of the input data file.
%
%  Local parameters:
%
%    Local, integer M, the number of columns of data.
%
%    Local, integer N, the number of entries in each column.
%
%    Local, real Z(NDIM,N), the set of data.
%
  fprintf ( 1, '\n' );
  timestamp;

  fprintf ( 1, '\n' );
  fprintf ( 1, 'HISTOGRAM_DISPLAY:\n' );
  fprintf ( 1, '  MATLAB version:\n' );
  fprintf ( 1, '\n' );
  fprintf ( 1, '  Read columns of data, assuming column 1 is the.\n' );
  fprintf ( 1, '  (average) X value, the other columns are histograms.\n' );
  fprintf ( 1, '  Display a stacked histogram of all the data.\n' );

  if ( s_len_trim ( input_file_name ) <= 0 )
    fprintf ( 1, '\n' );
    input_file_name = input ( 'Enter the name of the input file.' );
  end

  [ m, n ] = dtable_header_read ( input_file_name );
%
%  M had better be at least 2!
%
  if ( m < 2 )
    fprintf ( 1, '\n' );
    fprintf ( 1, 'HISTOGRAM_DISPLAY - Fatal error!\n' );
    fprintf ( 1, '  The number of columns of data must be at least 2!\n' );
    error ( 'HISTOGRAM_DISPLAY - Fatal error!' );
  end
% 
%  Read the point set.
%
  z = dtable_data_read ( input_file_name, m, n );
  z = z';
%
%  Assume that column 1 is the (average) X coordinate, and that all other columns
%  are sets of Y coordinates.  Plot the Y values as stacked bars.
%
  title ( input_file_name );

  bar3 ( z(:,1), z(:,2:m), 'stacked' );

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

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