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

// Global variable and mutex
int shared_variable = 0;
pthread_mutex_t mutex;

// Function to be executed by threads
void *update_shared_variable(void *arg) {
    pthread_mutex_lock(&mutex);   // Lock the access to the variable
    shared_variable++;           // Update the shared variable
    printf("Updated value: %d\n", shared_variable);
    pthread_mutex_unlock(&mutex); // Unlock the access to the variable
    pthread_exit(NULL);
}

int main() {
    pthread_t thread1, thread2;

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

    // Create the threads
    pthread_create(&thread1, NULL, update_shared_variable, NULL);
    pthread_create(&thread2, NULL, update_shared_variable, NULL);

    // Wait for the threads to finish
    pthread_join(thread1, NULL);
    pthread_join(thread2, NULL);

    // Destroy the mutex
    pthread_mutex_destroy(&mutex);

    return 0;
}