semaphore

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>
#include <unistd.h>

#define BUFFER_SIZE 5

int buffer[BUFFER_SIZE];
int in = 0, out = 0;

sem_t mutex, full, empty;

void *producer(void *arg) {
    while (1) {
        int item = rand() % 100;
        sem_wait(&empty);
        sem_wait(&mutex);


        buffer[in] = item;
        printf("Produced item: %d\n", item);
        in = (in + 1) % BUFFER_SIZE;

        sem_post(&mutex);
        sem_post(&full);

        sleep(1);
    }
}

void *consumer(void *arg) {
    while (1) {
        int item;
        sem_wait(&full);
        sem_wait(&mutex);

        item = buffer[out];
        printf("Consumed item: %d\n", item);
        out = (out + 1) % BUFFER_SIZE;

        sem_post(&mutex);
        sem_post(&empty);

        sleep(2);
    }
}

int main() {
    pthread_t prod_thread, cons_thread;

    sem_init(&mutex, 0, 1);
    sem_init(&full, 0, 0);
    sem_init(&empty, 0, BUFFER_SIZE);

    pthread_create(&prod_thread, NULL, producer, NULL);
    pthread_create(&cons_thread, NULL, consumer, NULL);

    pthread_join(prod_thread, NULL);
    pthread_join(cons_thread, NULL);
    return 0;
}