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

using namespace std;

# include "prime.hpp"

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

double cpu_time ( )

//****************************************************************************80
//
//  Purpose:
// 
//    CPU_TIME reports the elapsed CPU time.
//
//  Discussion:
//
//    The data available to this routine through "CLOCK" is not very reliable,
//    and hence the values of CPU_TIME returned should not be taken too 
//    seriously, especially when short intervals are being timed.
//
//  Licensing:
//
//    This code is distributed under the MIT license. 
//
//  Modified:
//
//    23 September 2008
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Output, double CPU_TIME, the current total elapsed CPU time in second.
//
{
  double value;

  value = ( double ) clock ( ) 
        / ( double ) CLOCKS_PER_SEC;

  return value;
}
//****************************************************************************80

int prime_number ( int n )

//****************************************************************************80
//
//  Purpose:
//
//    PRIME_NUMBER returns the number of primes between 1 and N.
//
//  Discussion:
//
//    A naive algorithm is used.
//
//    Mathematica can return the number of primes less than or equal to N
//   by the command PrimePi[N].
//
//                N  PRIME_NUMBER
//
//                1           0
//               10           4
//              100          25
//            1,000         168
//           10,000       1,229
//          100,000       9,592
//        1,000,000      78,498
//       10,000,000     664,579
//      100,000,000   5,761,455
//    1,000,000,000  50,847,534
//
//  Licensing:
//
//    This code is distributed under the MIT license. 
//
//  Modified:
//
//    23 April 2009
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int N, the maximum number to check.
//
//    Output, int PRIME_NUMBER, the number of prime numbers up to N.
//
{
  int i;
  int j;
  int prime;
  int total;

  total = 0;

  for ( i = 2; i <= n; i++ )
  {
    prime = 1;
    for ( j = 2; j < i; j++ )
    {
      if ( ( i % j ) == 0 )
      {
        prime = 0;
        break;
      }
    }
    total = total + prime;
  }
  return total;
}
//****************************************************************************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:
//
//    24 September 2003
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    None
//
{
# 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 );

  cout << time_buffer << "\n";

  return;
# undef TIME_SIZE
}