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

//Global variables
const int N=1000000;
const int tNUM = 4;
int array[1000000];
int count[4];

//function prototypes
int count3s(void);
void *count3s_thread(void *);

int main()
{
    int i, result;
//    srand(time(0));

    for (i = 0; i < N; i++)
	array[i] = rand()%100 + 1;
    result = count3s();
    printf("There were %d 3's\n",result);
    exit(0);
}
// This function creates tNUM threads
int count3s(void)
{
    int i;
    int thr_data[tNUM];
    int countt = 0;
    pthread_t thr[tNUM];
    for (i = 0; i < tNUM; i++) {
	thr_data[i] = i;
	pthread_create(&thr[i], NULL, count3s_thread, (void *)&thr_data[i]);
    }

    /* block until all threads complete */
    for (i = 0; i < tNUM; ++i) {
        pthread_join(thr[i], NULL);
        countt += count[i];
    }

    return countt;
}

// The funtion that each will execute
void *count3s_thread(void *id)
{
// Compute the portion of the array that this thread should search
     int myid = *(int *)id, cnt3 = 0, i;
     int length_per_thread = N/tNUM;
     int start = myid * length_per_thread;

     for ( i = start; i < start + length_per_thread; i++)
	if(array[i] == 3)
	   cnt3++;

     count[myid] = cnt3;

     pthread_exit(NULL);
}