#include "shared.h"

int
ptest (unsigned long num, char * filename) { 

  unsigned long primes[num]; // array holding primes
  unsigned long pfound, cnum, count;
  unsigned long p = num;
  FILE *fp;
  
  /* set up search */
  pfound = 1; // found primes
  cnum = 3; // current number
  primes[0] = 2; // give the first prime

  fp = fopen(filename, "w");
  fprintf(fp, "%d\n", 2); // print the first prime
  
  while (pfound != p) {

    /* check % != 0 for each found prime */
    count = 0;
    for (int i = 0; i < pfound; i++) {
      if ( cnum % primes[i] == 0) { // speed increase -- HOMEWORK 6
        break;
      }
      else
        count++;
    }

    /* if % !=0 for all found primes, add cnum to list */
    if (count == pfound) {
      primes[pfound] = cnum;
      fprintf(fp, "%d\n", cnum);
      pfound++;
    }

    cnum = cnum + 2; // don't check evens
  }

  fclose(fp);
  printf("last prime: %d\n", primes[p-1]); // print last prime
  
  return 0;
}