Better thread example

thread.c

@@ -1,14 +1,32 @@
 #include <pthread.h>
 #include <stdio.h>
 
+pthread_mutex_t lock;
+int             counter = 0;
+
 void *worker(void *arg) {
-    printf("Hello from thread\n");
+    printf("Hello from %s!\n", (char *)arg);
+    for (int i = 0; i < 100000; i++) {
+        pthread_mutex_lock(&lock);
+        counter++;
+        pthread_mutex_unlock(&lock);
+    }
     return NULL;
 }
 
 int main() {
-    pthread_t thread;
-    pthread_create(&thread, NULL, worker, NULL);
-    pthread_join(thread, NULL);
+    pthread_t thread1, thread2;
+
+    pthread_mutex_init(&lock, NULL);
+
+    pthread_create(&thread1, NULL, worker, "Thread1");
+    pthread_create(&thread2, NULL, worker, "Thread2");
+
+    pthread_join(thread1, NULL);
+    pthread_join(thread2, NULL);
+
+    pthread_mutex_destroy(&lock);
+
+    printf("Counter value: %d\n", counter);
     return 0;
 }