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

#define TEST( f, x ) ( *( f+( x )/16 )&( 1<<( ( ( x )%16L )/2 ) ) )
#define SET( f, x ) *( f+( x )/16 )|=1<<( ( ( x )%16L )/2 )

int
main (int argc, char *argv[])
{
  unsigned char *feld = NULL, *zzz = NULL;
  unsigned long teste = 1, max, mom, hits = 1, count, alloc, s = 0, e = 1;
  time_t begin;
  if (argc > 1)
    max = atol (argv[1]) + 10000;
  else
    max = 14010000L;

  zzz = feld = malloc (alloc = (((max -= 10000L) >> 4) + 1L));
  if (feld)
    {
      memset (zzz, 0, alloc);
      printf ("Searching prime numbers to : %ld\n", max);
      begin = time (NULL);
      while ((teste += 2) < max)
        if (!TEST (feld, teste))
          {
            if (++hits % 2000L == 0)
              {
                printf (" %ld. prime number\x0d", hits);
                fflush (stdout);
              }
            for (mom = 3L * teste; mom < max; mom += teste << 1)
              SET (feld, mom);
          }
      printf (" %ld prime numbers found in %ld secs.\n\nShow prime numbers",
              hits, time (NULL) - begin);
      while (s < e)
        {
          printf ("\n\nStart of Area : ");
          fflush (stdout);
          scanf ("%ld", &s);
          printf ("End of Area : ");
          fflush (stdout);
          scanf ("%ld", &e);
          if (s <= 2 && e >= 2)
            printf ("%ld\t", 2L);
          count = s - 2;
          if (s % 2 == 0)
            count++;
          while ((count += 2) < e)
            if (!TEST (feld, count) && count != 1)
              printf ("%ld\t", count);
        }
      free (feld);
    }
  else
    {
      puts ("Memory allocation failure.");
      exit (EXIT_FAILURE);
    }
  return 0;
}