# include <math.h>
# include <stdio.h>
# include <stdlib.h>
# include <time.h>
#
# include "middle_square.h"

int main ( );
void middle_square_next_test ( );
void timestamp ( );

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

int main ( )

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

    middle_square_test() tests middle_square().

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    16 September 2022

  Author:

    John Burkardt
*/
{
  timestamp ( );
  printf ( "\n" );
  printf ( "middle_square_test():\n" );
  printf ( "  C version\n" );
  printf (  "  Test middle_square()\n" );

  middle_square_next_test ( );
/*
  Terminate.
*/
  printf ( "\n" );
  printf ( "middle_square_test():\n" );
  printf ( "  Normal end of execution.\n" );
  printf ( "\n" );
  timestamp ( );

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

void middle_square_next_test ( )

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

    middle_square_next_test() tests middle_square_next().

  Discussion:

    This function simply demonstrates the results of 10 successive calls
    to middle_square_next(), for a range of values of d.

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    16 September 2022

  Author:

    John Burkardt
*/
{
  long long int d;
  long long int divisor;
  long long int i;
  long long int s;

  printf ( "\n" );
  printf ( "middle_square_next_test():\n" );
  printf ( "  middle_square_next ( s, d ) applies the middle square algorithm\n" );
  printf ( "  using a 2*d digit seed.\n" );

  for ( d = 1; d <= 5; d++ )
  {
    printf ( "\n" );
    printf ( "  Using d = %lld\n", d );
    printf ( "\n" );

    divisor = ( long long int ) pow ( 10, 2 * d );
    s = ( 2147483647 % divisor );

    for ( i = 0; i <= 10; i++ )
    {
      printf ( "  %2lld  %lld\n", i, s );
      s = middle_square_next ( s, d );
    }
  }

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

void timestamp ( )

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

    timestamp() prints the current YMDHMS date as a time stamp.

  Example:

    17 June 2014 09:45:54 AM

  Licensing:

    This code is distributed under the MIT license. 

  Modified:

    01 May 2021

  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
}