# include <stdbool.h>
# include <stdio.h>
# include <stdlib.h>
# include <time.h>

int main ( int argc, char *argv[] );
void node_write ( char *output_filename, int m, int n, double table[] );
void timestamp ( );

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

int main ( int argc, char *argv[] )

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

    random_nodes() creates random nodes and writes them in a triangle file.

  Licensing:

    This code is distributed under the GNU LGPL license. 

  Modified:

    21 September 2016

  Author:

    John Burkardt
*/
{
  char filename[255];
  int i;
  int j;
  int m;
  int n;
  int seed;
  bool verbose = false;
  double *x;

  if ( verbose )
  {
    timestamp ( );
    printf ( "\n" );
    printf ( "random_nodes():\n" );
    printf ( "  C version\n" );
    printf ( "  Create a file of N random nodes in 2D.\n" );
  }

  m = 2;
  n = atoi ( argv[1] );
  if ( verbose )
  {
    printf ( "  Number of nodes N = %d\n", n );
  }
/*
  Create data.
*/
  x = ( double * ) malloc ( m * n * sizeof ( double ) );

  seed = time ( 0 );
  srand ( seed );

  for ( i = 0; i < n; i++ )
  {
    for ( j = 0; j < m; j++ )
    {
      x[j+i*m] = ( double ) rand ( ) / ( double ) RAND_MAX;
    }
  }
/*
  Write data to triangle node file.
*/
  sprintf ( filename, "nodes_n%d.node", n );
  if ( verbose )
  {
    printf ( "  Created '%s'\n", filename );
  }

  node_write ( filename, m, n, x );
/*
  Free memory.
*/
  free ( x );
/*
  Terminate.
*/
  if ( verbose )
  {
    printf ( "\n" );
    printf ( "random_nodes():\n" );
    printf ( "  Normal end of execution.\n" );
    printf ( "\n" );
    timestamp ( );
  }

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

void node_write ( char *filename, int m, int n, double x[] )

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

    node_write() writes a triangle node file.

  Discussion:

    An R8MAT is an array of R8's.

  Licensing:

    This code is distributed under the GNU LGPL license. 

  Modified:

    01 June 2009

  Author:

    John Burkardt

  Input:

    char *FILENAME, the output filename.

    int M, the spatial dimension.

    int N, the number of points.

    double X[M*N], the data.
*/
{
  int i;
  int j;
  FILE *output;
/*
  Open the file.
*/
  output = fopen ( filename, "wt" );

  if ( !output )
  {
    fprintf ( stderr, "\n" );
    fprintf ( stderr, "node_write(): Fatal error!\n" );
    fprintf ( stderr, "  Could not open the file '%s'.\n", filename );
    exit ( 1 );
  }
/*
  TRIANGLE requires a header line.
*/
  fprintf ( output, "%d  %d  0  0\n", n, m );
/*
  Write the data.
*/
  for ( i = 0; i < n; i++ )
  {
    fprintf ( output, "%d  ", i );
    for ( j = 0; j < m; j++ )
    {
      fprintf ( output, "  %24.16g", x[j+i*m] );
    }
    fprintf ( output, "\n" );
  }
/*
  Close the file.
*/
  fclose ( output );

  return;
}
/******************************************************************************/

void timestamp ( )

/******************************************************************************/
/*
  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 GNU LGPL license. 

  Modified:

    24 September 2003

  Author:

    John Burkardt
*/
{
# define TIME_SIZE 40

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

  now = time ( NULL );
  tm = localtime ( &now );

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

  printf ( "%s\n", time_buffer );

  return;
# undef TIME_SIZE
}