# include <cmath>
# include <cstring>
# include <cstdlib>
# include <ctime>
# include <fstream>
# include <iomanip>
# include <iostream>

using namespace std;

int main ( );
void timestamp ( );

//****************************************************************************80

int main ( )

//****************************************************************************80
//
//  Purpose:
//
//    temperature_scatter3d() creates a 3D scatter plot of temperature.
//
//  Licensing:
//
//    This code is distributed under the MIT license.
//
//  Modified:
//
//    22 August 2025
//
//  Author:
//
//    John Burkardt
//
{
  string command_filename = "temperature_scatter3d_commands.txt";
  ofstream command;
  string data_filename = "temperature_data.txt";
  string plot_filename = "temperature_scatter3d.png";

  timestamp ( );
  cout << "\n";
  cout << "temperature_scatter3d():\n";
  cout << "  C++ version\n";
  cout << "  Create a 3D scatter plot of\n";
  cout << "  January temperatures across the US.\n";
  cout << "  Create corresponding gnuplot() input files.\n";
//
//  Create the command file.
//
  command.open ( command_filename.c_str ( ) );

  command << "# " << command_filename << "\n";
  command << "#\n";
  command << "# Usage:\n";
  command << "#  gnuplot < " << command_filename << "\n";
  command << "#\n";
  command << "set term png\n";
  command << "set output '" << plot_filename << "'\n";
  command << "set xlabel '<--- Longitude --->'\n";
  command << "set ylabel '<--- Latitude --->'\n";
  command << "set zlabel '<--- Temperature --->'\n";
  command << "set title 'January temperatures across US'\n";
  command << "set view equal xyz\n";
  command << "set grid\n";
  command << "unset key\n";
  command << "splot '" << data_filename 
          << "' using 2:3:1 with points pt 7 ps 2\n";
  command << "quit\n";

  command.close ( );
//
//  Terminate.
//
  cout << "\n";
  cout << "temperature_scatter3d():\n";
  cout << "  Normal end of execution.\n";
  cout << "\n";
  timestamp ( );

  return 0;
}
//****************************************************************************80

void timestamp ( )

//****************************************************************************80
//
//  Purpose:
//
//    timestamp() prints the current YMDHMS date as a time stamp.
//
//  Example:
//
//    31 May 2001 09:45:54 AM
//
//  Licensing:
//
//    This code is distributed under the MIT license. 
//
//  Modified:
//
//    19 March 2018
//
//  Author:
//
//    John Burkardt
//
{
# define TIME_SIZE 40

  static char time_buffer[TIME_SIZE];
  const struct std::tm *tm_ptr;
  std::time_t now;

  now = std::time ( NULL );
  tm_ptr = std::localtime ( &now );

  std::strftime ( time_buffer, TIME_SIZE, "%d %B %Y %I:%M:%S %p", tm_ptr );

  std::cout << time_buffer << "\n";

  return;
# undef TIME_SIZE
}