6.c

/*
============================================================================
Name : 6
Author : Piyush Singh
Description : Write a simple program to create three threads.
Date: 18th Sep, 2025.
============================================================================
*/

#include <stdio.h>        // For printf()
#include <stdlib.h>       // For exit()
#include <pthread.h>      // For pthread_create(), pthread_join()
#include <unistd.h>       // For sleep()

// Thread function — each thread runs this
void* thread_task(void* arg) 
{
    int thread_num = *(int*)arg;  // Convert argument to int
    printf("🧵 Thread %d is running\n", thread_num);
    sleep(1);  // Optional: simulate work
    printf("✅ Thread %d has finished\n", thread_num);
    return NULL;
}

int main() 
{
    pthread_t threads[3];     // Array to hold thread IDs
    int thread_ids[3] = {1, 2, 3};  // Thread identifiers

    // Step 1: Create 3 threads
    for (int i = 0; i < 3; i++) 
    {
        if (pthread_create(&threads[i], NULL, thread_task, &thread_ids[i]) != 0) 
        {
            perror("❌ Failed to create thread");
            exit(1);
        }
    }

    // Step 2: Wait for all threads to finish
    for (int i = 0; i < 3; i++) 
        pthread_join(threads[i], NULL);

    printf("🎉 All threads have completed\n");
    return 0;
}


// Output order may vary because threads run independently.

/*
Output: 
./6                                                                        ─╯
🧵 Thread 2 is running!
🧵 Thread 1 is running!
🧵 Thread 3 is running!
✅ All threads finished.
*/