#include <time.h>
int main() {

  /*Declare Variables*/
  clock_t start, end, begin, stop;
  double runTime, time;
  start = clock();
  int i,primes,num,count,total;

  /*Assign Variables*/
  primes=0;
  num=1;
  begin = clock();

  /*Begin program, accept input*/
  system("cls");
  printf("Please enter the highest prime you want to generate to: ");
  scanf("%d",&total);
  printf("\n");

  /*Begin MATHS!*/
  #pragma omp parallel for schedule(dynamic) reduction(+ : primes)
  for (num = 1; num <= total; num++) {
    i=2;

    while(i<=num) {
      if(num%i==0)
      break;
      i++;
    }

    if(i==num) {
      primes++;
    }

    num++;
    stop = clock();
    time = (stop - begin) / (double)CLOCKS_PER_SEC;

    if (time < 0.1) {
      count++;
    }
    else {
      system("cls");
      printf("Performing %d calculations per second; %d prime numbers calculated\n",count,primes);
      begin = clock();
      count=0;
    }

  }

  /*Print results*/
  end = clock();
  runTime = (end - start) / (double) CLOCKS_PER_SEC;
  printf("This machine calculated all %d prime numbers under %d in %g seconds\n",primes,total,runTime);
  return 0;
}