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

#define NUM_THREADS 4
#define TOT_COUNT 100000000

float randNumGen(){


   int random_value = rand();
   float unit_random = random_value / (float) RAND_MAX; //m
   return unit_random;
}

void *doCalcs(void *threadid)
{
   long longTid;
   longTid = (long)threadid;

   int tid = (int)longTid;

   float *in_count = (float *)malloc(sizeof(float));
   *in_count=0;

   float tot_iterations= TOT_COUNT/NUM_THREADS;

   int counter=0;

   for(counter=0;counter<tot_iterations;counter++){
      float x = randNumGen();
      float y = randNumGen();

      float result;
      result = sqrt((x*x) + (y*y));

      if(result<1){
         *in_count+=1;
      }

   }

   if(tid==0){
      float remainder = TOT_COUNT%NUM_THREADS;

      for(counter=0;counter<remainder;counter++){
      float x = randNumGen();
      float y = randNumGen();

      float result;
      result = sqrt((x*x) + (y*y));

      if(result<1){
         *in_count+=1;
      }
   }
   }
   pthread_exit((void *)in_count);
}

int main(int argc, char *argv[])
{
   pthread_t threads[NUM_THREADS];
   int rc;
   long t;
   void *status;
   float tot_in=0;

   for(t=0;t<NUM_THREADS;t++){
     rc = pthread_create(&threads[t], NULL, doCalcs, (void *)t);
     if (rc){
       printf("ERROR; return code from pthread_create() is %d\n", rc);
       exit(-1);
       }
     }

   for(t=0;t<NUM_THREADS;t++){

      pthread_join(threads[t], &status);

      tot_in+=*(float*)status;

     }
     printf("Value for Pi is %f \n",4*(tot_in/TOT_COUNT));

   pthread_exit(NULL);
}