dpp

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <omp.h>

#define NUM_PHILOSOPHERS 5
#define THINKING_TIME 1
#define EATING_TIME 2

omp_lock_t forks[NUM_PHILOSOPHERS];

void think(int philosopher_id) {
    printf("Philosopher %d is thinking.\n", philosopher_id);
    sleep(THINKING_TIME);
}

void eat(int philosopher_id) {
    printf("Philosopher %d is eating.\n", philosopher_id);
    sleep(EATING_TIME);
}

int main() {
    // Initialize locks for forks
    for (int i = 0; i < NUM_PHILOSOPHERS; i++) {
        omp_init_lock(&forks[i]);
    }

    #pragma omp parallel num_threads(NUM_PHILOSOPHERS)
    {
        int philosopher_id = omp_get_thread_num();
        int left_fork = philosopher_id;
        int right_fork = (philosopher_id + 1) % NUM_PHILOSOPHERS;

        // Ensure the lower numbered fork is picked up first to prevent deadlock
        int first_fork = left_fork < right_fork ? left_fork : right_fork;
        int second_fork = left_fork < right_fork ? right_fork : left_fork;

        while (1) {
            think(philosopher_id);

            // Pick up the first fork
            omp_set_lock(&forks[first_fork]);
            printf("Philosopher %d picked up fork %d.\n", philosopher_id, first_fork);

            // Pick up the second fork
            omp_set_lock(&forks[second_fork]);
            printf("Philosopher %d picked up fork %d.\n", philosopher_id, second_fork);

            eat(philosopher_id);

            // Put down the forks
            omp_unset_lock(&forks[second_fork]);
            printf("Philosopher %d put down fork %d.\n", philosopher_id, second_fork);
            omp_unset_lock(&forks[first_fork]);
            printf("Philosopher %d put down fork %d.\n", philosopher_id, first_fork);
        }
    }

    // Destroy locks
    for (int i = 0; i < NUM_PHILOSOPHERS; i++) {
        omp_destroy_lock(&forks[i]);
    }

    return 0;
}