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

using namespace std;

# include "van_der_corput.H"

int main ( void );

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

int main ( void )

//****************************************************************************80
//
//  Purpose:
//
//    MAIN is the main program for VAN_DER_CORPUT_DATASET.
//
//  Discussion:
//
//    VAN_DER_CORPUT_DATASET generates a van der Corput dataset.
//
//    This program is meant to be used interactively.  It's also
//    possible to prepare a simple input file beforehand and use it
//    in batch mode.
//
//    The program requests input values from the user:
//
//    * BASE, the base of the sequence,
//    * SEED, the seed, a positive integer.
//    * N, the number of points to generate,
//
//    The program generates the data, writes it to the file
//
//      van_der_corput_BASE_SEED_N.txt
//
//    where "BASE", "SEED", and "N" are the numeric values specified by the
//    user, and then asks the user for more input.   To indicate that no further
//    computations are desired, it is enough to input a nonsensical
//    value, such as -1.
//
//  Modified:
//
//    12 April 2007
//
//  Author:
//
//    John Burkardt
//
{
  int base;
  char command[255];
  char file_out_name[255];
  int i;
  int n;
  double *r;
  int seed;
  int seed_init;
  char *string;

  timestamp ( );

  cout << "\n";
  cout << "VAN_DER_CORPUT_DATASET\n";
  cout << "  C++ version\n";
  cout << "\n";
  cout << "  Compiled on " << __DATE__ << " at " << __TIME__ << ".\n";
  cout << "\n";
  cout << "  Generate a van der Corput dataset.\n";
  cout << "\n";
  cout << "  This program is meant to be used interactively.\n";
  cout << "  It is also possible to prepare a simple input\n";
  cout << "  file beforehand and use it in batch mode.\n";
  cout << "\n";
  cout << "  The program requests input values from the user:\n";
  cout << "\n";
  cout << "  * BASE, the base,\n";
  cout << "  * SEED, a positive integer.\n";
  cout << "  * N, the number of points to generate,\n";

  cout << "\n";
  cout << "  The program generates the data, writes it to the file\n";
  cout << "\n";
  cout << "    van_der_corput_BASE_SEED_N.txt\n";
  cout << "\n";
  cout << "  where ""BASE"", ""SEED"" and ""N"" are the numeric values\n";
  cout << "  specified by the user, and then asks the user for more input.\n";
  cout << "\n";
  cout << "  To indicate that no further computations are\n";
  cout << "  desired, it is enough to input a nonsensical value,\n";
  cout << "  such as -1.\n";

  for ( ; ; )
  {
    cout << "  *\n";
    cout << " *\n";
    cout << "*  Ready to generate a new dataset:\n";
    cout << " *\n";
    cout << "  *\n";

    cout << "\n";
    cout << "  Enter BASE, the van der Corput base,\n";
    cout << "  which is often a prime number:\n";
    cout << "  (Try '2' if you don't have a preference.)\n";
    cout << "  (Any value of 1 or less terminates execution).\n";

    cin >> base;

    if ( cin.rdstate ( ) )
    {
      cin.clear ( );
  
      cout << "\n";
      cout << "VAN_DER_CORPUT_DATASET - Fatal error!\n";
      cout << "  An I/O error occurred while trying to read BASE.\n";
      cout << "  Abnormal end of execution.\n";
      break;
    }

    if ( base <= 1 )
    {
      cout << "\n";
      cout << "VAN_DER_CORPUT_DATASET\n";
      cout << "  The input value of BASE = " << base << "\n";
      cout << "  is interpreted as a request for termination.\n";
      cout << "  Normal end of execution.\n";
      break;
    }

    cout << "\n";
    cout << "  Enter SEED, which is 0 or a positive integer.\n";
    cout << "  (Try '0' or '1' if you don't have a preference.)\n";
    cout << "  (Any negative value terminates execution).\n";

    cin >> seed;

    if ( cin.rdstate ( ) )
    {
      cin.clear ( );
  
      cout << "\n";
      cout << "VAN_DER_CORPUT_DATASET - Fatal error!\n";
      cout << "  An I/O error occurred while trying to read SEED.\n";
      cout << "  Abnormal end of execution.\n";
      break;
    }

    if ( seed < 0 )
    {
      cout << "\n";
      cout << "VAN_DER_CORPUT_DATASET\n";
      cout << "  The input value of SEED = " << seed << "\n";
      cout << "  is interpreted as a request for termination.\n";
      cout << "  Normal end of execution.\n";
      break;
    }

    cout << "\n";
    cout << "  Enter N, the number of points to generate:\n";
    cout << "  (Try '25' if you don't have a preference.)\n";
    cout << "  (0 or any negative value terminates execution).\n";

    cin >> n;

    if ( cin.rdstate ( ) )
    {
      cin.clear ( );
  
      cout << "\n";
      cout << "VAN_DER_CORPUT_DATASET - Fatal error!\n";
      cout << "  An I/O error occurred while trying to read N.\n";
      cout << "  Abnormal end of execution.\n";
      break;
    }

    if ( n < 1 )
    {
      cout << "\n";
      cout << "VAN_DER_CORPUT_DATASET\n";
      cout << "  The input value of N = " << n << "\n";
      cout << "  is interpreted as a request for termination.\n";
      cout << "  Normal end of execution.\n";
      break;
    }

    seed_init = seed;

    r = new double[n];

    i4_to_van_der_corput_sequence ( seed, base, n, r );

    sprintf ( file_out_name, "van_der_corput_%d_%d_%d.txt", base, seed, n );

    van_der_corput_write ( n, seed_init, base, r, file_out_name );

    delete [] r;

    cout << "\n";
    cout << "  The data was written to the file \"" 
      << file_out_name << "\".\n";
  }

  cout << "\n";
  timestamp ( );

  return 0;
}