generate primes - non-optimized naive algorithm!

prime.c

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

char is_prime(int number) {
  int i;
  int limit = number/2;

  for(i=2;i<=limit;i++) { if(number % i == 0) return 0; }
  return 1;
};

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

  if(argc != 4) {
    printf("usage: %s start max_number filename\n", argv[0]);
    exit(1);
  }


  int start = atoi(argv[1]);
  int max = atoi(argv[2]);

  FILE *result = fopen(argv[3], "w");

  int i;
  int hits = 0;

  for(i=start;max==0||hits<max;i++) {
    if(is_prime(i)) {
      fprintf(result, "%d\n", i);
      fflush(result);
      hits++;
    }
  }

  fclose(result);

  return 0;
}