tsdwl: add exam

1 files changed, 59 insertions, 0 deletions

diff --git a/Year_3/TSDWL/ex_20170201/thread.c b/Year_3/TSDWL/ex_20170201/thread.c
new file mode 100644
index 0000000..34ba440
--- /dev/null
+++ b/Year_3/TSDWL/ex_20170201/thread.c
@@ -0,0 +1,59 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <time.h>
+#include <string.h>
+
+pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+int sample = 50;
+
+void*
+fn(void* arg)
+{
+    char* th = (char*) arg;
+    int new_sample;
+
+    char indent[3] = "";
+    if (strcmp(th, "B") == 0)
+        strcpy(indent, "\t");
+    else if (strcmp(th, "C") == 0)
+        strcpy(indent, "\t\t");
+
+    while (1) {
+        new_sample = (rand() % 81) + 10;
+        pthread_mutex_lock(&mutex);
+
+        printf("%sSono il thread %s: sample valeva %d, adesso vale %d\n", indent, th, sample, new_sample);
+        if (sample != new_sample) {
+            sample = new_sample;
+            pthread_mutex_unlock(&mutex);
+        } else {
+            pthread_mutex_unlock(&mutex);
+            break;
+        }
+
+    }
+
+    printf("%sSono il thread %s, e sto uscendo!\n", indent, th);
+
+    pthread_exit(NULL);
+}
+
+int
+main()
+{
+    pthread_t th[3];
+    srand(time(NULL));
+
+    pthread_create(&th[0], NULL, &fn, (void*) "A");
+    pthread_create(&th[1], NULL, &fn, (void*) "B");
+    pthread_create(&th[2], NULL, &fn, (void*) "C");
+
+    pthread_join(th[0], NULL);
+    pthread_join(th[1], NULL);
+    pthread_join(th[2], NULL);
+
+    printf("Il valore finale di sample e' %d\n", sample);
+
+    return 0;
+}