# include <math.h>
# include <stdio.h>
# include <stdlib.h>
# include <string.h>

# include "tsp_display.h"

/******************************************************************************/

void tsp_display ( char *prefix, int n, double *x2 )

/******************************************************************************/
/*
  Purpose:

    tsp_display() plots cities and a tour connecting them.

  Discussion:

    If a "round trip" is desired, then the x2 array must repeat the
    first city at the end.

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    12 June 2026

  Author:

    John Burkardt

  Input:

    char *prefix: a string that defines the name of
    the problem.  It is also used to create file names needed for
    input to gnuplot.

    int n: the number of cities.

    double x[n*2]: the x and y coordinates of the cities.
*/
{
  char command_filename[80];
  FILE *command;
  FILE *data;
  char data_filename[80];
  int i;
/*
  Create the data file.
*/
  strcpy ( data_filename, prefix );
  strcat ( data_filename, "_data.txt" );
  data = fopen ( data_filename, "wt" );
  for ( i = 0; i < n; i++ )
  {
    fprintf ( data, "%14.6g  %14.6g\n", x2[2*i], x2[2*i+1] );
  }
  fclose ( data );
  printf ( "  Created data file '%s'\n", data_filename );
/*
  Create the command file.
*/
  strcpy ( command_filename, prefix );
  strcat ( command_filename, "_commands.txt" );
  command = fopen ( command_filename, "wt" );

  fprintf ( command, "# %s\n", command_filename );
  fprintf ( command, "#\n" );
  fprintf ( command, "# Usage:\n" );
  fprintf ( command, "#  gnuplot < %s\n", command_filename );
  fprintf ( command, "#\n" );
  fprintf ( command, "set term png\n" );
  fprintf ( command, "set output '%s.png'\n", prefix );
  fprintf ( command, "set xlabel '<--- X --->'\n" );
  fprintf ( command, "set ylabel '<--- Y --->'\n" );
  fprintf ( command, "set title '%s'\n", prefix );
  fprintf ( command, "set grid\n" );
  fprintf ( command, "unset key\n" );
  fprintf ( command, "set style data lines\n" );
  fprintf ( command, "plot '%s' using 1:2 lw 3 linecolor rgb 'blue', \\\n", data_filename );
  fprintf ( command, "     '%s' using 1:2 with points pointtype 7 pointsize 3 linecolor rgb 'green'\n", data_filename );
  fprintf ( command, "quit\n" );
  fclose ( command );
  printf ( "  Created command file '%s'\n", command_filename );

  return;
}