#include <stdio.h>
#include <math.h>


main(int argc, char *argv[])
{
   int i, j, limit;
   int start, end;          /* range of numbers to search */
   int number_of_primes=0;  /* number of primes found */
   int number_of_41primes=0;/* number of 4n+1 primes found */
   int number_of_43primes=0;/* number of 4n-1 primes found */
   int prime;               /* is the number prime? */
   int print_primes=0;      /* should each prime be printed? */

   start = atoi(argv[1]);
   end = atoi(argv[2]);
   if (!(start % 2)) start++;

   if (argc == 4 && atoi(argv[3]) != 0) print_primes = 1;
   printf("Range to check for Primes: %d - %d\n\n",start, end);

   for(i = start; i <= end; i += 2) {

      limit = (int) sqrt((float)i) + 1;
      prime = 1; /* assume number is prime */
      j = 3;
      while (prime && (j <= limit)) {
         if (i%j == 0) prime = 0;
         j += 2;
      }

      if (prime) {
	  if (print_primes) printf("%5d is prime\n",i);
        number_of_primes++;
        if (i%4 == 1) number_of_41primes++;
        if (i%4 == 3) number_of_43primes++;
      }
   }

   printf("\nProgram Done.\n %d primes found\n",number_of_primes);
   printf("\nNumber of 4n+1 primes found: %d\n",number_of_41primes);
   printf("\nNumber of 4n-1 primes found: %d\n",number_of_43primes);
}