#include <stdio.h>
#include <pthread.h>
#include <unistd.h>
#include <sys/types.h>
#include <time.h>


#define nt 5
#define N 4

void* master_fun (void *threadarg);
void* slave_fun (void *threadarg);
int dot_prod(int x[], int y[]);

pthread_mutex_t lock_s;

int V1[N];
int V2[N];
int master_flag=0;


int main(int argc, char* argv[])
{
	srand(time(NULL));
	pthread_t threads[nt];
	unsigned int id[nt];

	int rc,t;

//semaphores declaration out of main
	if(pthread_mutex_init(&lock_s, NULL) != 0)
	{
		return 1;
	}
//CREATION THREADS
	for(t=0;t<nt;t++)
	{
		printf("In main thread#%d are being created : id--> ",t);
		if(t==4)
		{
			rc=pthread_create(&threads[t], NULL, master_fun,(void*) &t);
			printf("(%u)",t);
		}
		else
		{
			rc=pthread_create(&threads[t], NULL, slave_fun, (void*) &t);
			printf("(%u)",t);

		}
		printf("\n");

		if(rc)
		{
			printf("Error; return %d as value of error\n", rc);
			return(-1);
		}
	}


//WAIT THREADS TO EXECUTE
	for(t=0;t<nt;t++)
	{
		rc=pthread_join(threads[t], NULL);

		if(rc)
		{
			printf("Error; return %d as value of error\n", rc);
			return(-1);
		}
	}


	pthread_mutex_destroy(&lock_s);

}

void* master_fun(void *threadarg)
{
	int i;
	for(i=0;i<N;i++)
	{
		V1[i]=rand()%20-10;
		V2[i]=rand()%20-10;
		printf("\n--/%d/--\n",V1[i]);
		printf("\n--/%d/--\n",V2[i]);
	}
	master_flag=1;
	pthread_exit(NULL);

}

void* slave_fun (void *threadarg)
{
	int PS,i;
	int a1[N/4],a2[N/4];

	pthread_mutex_lock(&lock_s);

	while(master_flag==0)
		;

	//dot product
	if((*(int*)threadarg)==0)
	{
		for(i=0;i<N/4;i++)
			a1[i]=V1[i];
			a2[i]=V2[i];

		PS=dot_prod(a1,a2);
		printf("\nprod_scal di mamt #1: %d\n",PS);
	}
		if((*(int*)threadarg)==1)
	{
		for(i=0;i<N/4;i++)
			a1[i]=V1[i];
			a2[i]=V2[i];

		PS=dot_prod(a1,a2);
		printf("\nprod_scal di mamt #2: %d\n",PS);
	}
		if((*(int*)threadarg)==2)
	{
		for(i=0;i<N/4;i++)
			a1[i]=V1[i];
			a2[i]=V2[i];

		PS=dot_prod(a1,a2);
		printf("\nprod_scal di mamt #3: %d\n",PS);
	}
		if((*(int*)threadarg)==3)
	{
		for(i=0;i<N/4;i++)
			a1[i]=V1[i];
			a2[i]=V2[i];

		PS=dot_prod(a1,a2);
		printf("\nprod_scal di mamt #4: %d\n",PS);
	}

		pthread_mutex_unlock(&lock_s);
		pthread_exit(NULL);


}

int dot_prod(int x[], int y[])
{
	int P,i;

	P=0;
	for(i=0; i<N/4;i++)
	{

		P=P+x[i]*y[i];
	}

	return P;
}