/*Name: Sushant Baskota*/
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#define NUMBER_OF_POINTS 50000000


void *runner (void *param);

int circle_count = 0;
double random_double ()
{
  return random () / ((double) RAND_MAX + 1);
}

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

  if(argc<2||argc>2){
      printf("<number of threads> should be a positive integer");
      return 0;
  }

  int thikxa =atoi(argv[1]);
  if(thikxa<=0){
      printf("Number of threads needs to be more than 0");
      return 0;
  }
  int points_per_thread = NUMBER_OF_POINTS / thikxa;
  int i;
  double Pi;
  pthread_t workers[thikxa];
  srandom((unsigned)time(NULL));

  for(i=0; i<thikxa; i++)
    pthread_create(&workers[i], 0, runner, &points_per_thread);
  for(i=0; i<thikxa; i++)
    pthread_join(workers[i], NULL);

  Pi = 4.0*circle_count/NUMBER_OF_POINTS;

  printf("Pi: = %f\n", Pi);

  return 0;


}

void *runner(void *param)
{
    int POINTS;
    POINTS = *((int *)param);
    int i;
    int hit_count = 0;
    double x,y;
    for(i=0; i<POINTS; i++)
    {
        x=random_double()*2.0-1.0;
        y=random_double()*2.0-1.0;

        if(sqrt(x*x+y*y)<1.0)
            ++hit_count;
    }

    circle_count += hit_count;
    pthread_exit(0);
}