C Program

 #include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <pthread.h>

int SIZE=50000;

int TAIL;

int HEAD;

pid_t MYARRAY[50000];

pthread_mutex_t mutex;

pthread_cond_t condInserted;

pthread_cond_t condRemoved;

int isFull(){

if((HEAD+1)%SIZE==TAIL){

return 1;

}

return 0;

}

int isEmpty(){

if(HEAD==TAIL){

return 1;

}

return 0;

}

void * thread1(){

while(1){

pthread_mutex_lock(&mutex);//mutex object referenced by mutex shall be locked

if(isFull()){

printf("Full queue");

pthread_cond_wait(&condRemoved,&mutex);

}

pid_t tid = gettid();

HEAD = (HEAD+1)%SIZE;

MYARRAY[HEAD] = tid;

printf("\nWriter:%d\n",tid);

pthread_mutex_unlock(&mutex);//mutex object referenced by mutex  be unlocked

pthread_cond_signal(&condInserted);//call unblocks at least one of the threads that are blocked on the specified condition variable cond

usleep(300000);

}

}

void* thread2(){

while(1){

pthread_mutex_lock(&mutex);

pid_t a = -1;

pid_t tid = gettid();//returns the caller's thread ID

if(isEmpty()){

printf("Empty queue");

pthread_cond_wait(&condInserted,&mutex);//used to block on a condition variable

}

TAIL = (TAIL+1)%SIZE;

a = MYARRAY[TAIL];

MYARRAY[TAIL] = -1;

printf("\n\t\t\t\t\t\t\t\tReader : %d,READ:%d\n",tid,a);

pthread_mutex_unlock(&mutex);

pthread_cond_signal(&condRemoved);

usleep(200000);//suspends execution of the calling thread

       //for (at least) usec microseconds

}

}

int main() {

SIZE = 50000;

TAIL=HEAD=0;

pthread_mutex_init(&mutex,NULL);// initialises the mutex

pthread_cond_init(&condInserted,NULL);//initialises the condition variable

pthread_cond_init(&condRemoved,NULL);//initialises the condition variable

pthread_t writer_threads[20];

pthread_t reader_threads[2];

for(int i=0;i<20;i++){

pthread_create(&writer_threads[i],NULL,&thread1,NULL);

}

for (int i = 0; i < 2; i++) {

       pthread_create(&reader_threads[i], NULL, &thread2, NULL);

   }

    for (int i = 0; i < 20; i++) {

       pthread_join(writer_threads[i], NULL);

   }

   for (int i = 0; i < 2; i++) {

       pthread_join(reader_threads[i], NULL);

   }

pthread_mutex_destroy(&mutex);//shall destroy the mutex object referenced by mutex

pthread_cond_destroy(&condInserted);//destroy the given condition variable specified by cond

pthread_cond_destroy(&condRemoved);

return 0;

}