From 12eb2dc3d43e0a24e7713e1f470587ba97f3f2a0 Mon Sep 17 00:00:00 2001
From: Santo Cariotti <santo@dcariotti.me>
Date: Wed, 24 Nov 2021 22:21:27 +0100
Subject: tsdwl: add exam

---
 Year_3/TSDWL/ex_20170203/thread.c | 81 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 Year_3/TSDWL/ex_20170203/thread.c

(limited to 'Year_3/TSDWL/ex_20170203')

diff --git a/Year_3/TSDWL/ex_20170203/thread.c b/Year_3/TSDWL/ex_20170203/thread.c
new file mode 100644
index 0000000..3471f88
--- /dev/null
+++ b/Year_3/TSDWL/ex_20170203/thread.c
@@ -0,0 +1,81 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <time.h>
+#include <unistd.h>
+
+int n;
+pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+
+void*
+fnO(void* arg)
+{
+    int xrand;
+    int count = 0;
+
+    while (1) {
+        usleep(200 * 1000);
+        do {
+            xrand = rand();
+        } while ((xrand % 2) == 1);
+
+        count++;
+        pthread_mutex_lock(&mutex);
+        printf("Thread O, count = %d, old x = %d, x = %d, even = %d\n", count, n, n+xrand, ((n+xrand) % 2)==0);
+        n += xrand;
+
+        if ((count == 1000) || (count >= 10 && (n%2) == 0)) {
+            pthread_mutex_unlock(&mutex);
+            break;
+        }
+        pthread_mutex_unlock(&mutex);
+
+    }
+
+    printf("Thread O terminated.\n");
+    pthread_exit(NULL);
+}
+
+void*
+fnE(void* arg)
+{
+    int xrand;
+    int count = 0;
+
+    while (1) {
+        usleep(200 * 1000);
+        do {
+            xrand = rand();
+        } while ((xrand % 2) == 0);
+
+        count++;
+        pthread_mutex_lock(&mutex);
+        printf("\tThread E, count = %d, old x = %d, x = %d, odd = %d\n", count, n, n+xrand, ((n+xrand) % 2)==1);
+        n += xrand;
+
+        if ((count == 1000) || (count >= 10 && (n%2) == 1)) {
+            pthread_mutex_unlock(&mutex);
+            break;
+        }
+        pthread_mutex_unlock(&mutex);
+    }
+
+    printf("\tThread E terminated.\n");
+    pthread_exit(NULL);
+}
+
+int
+main()
+{
+    pthread_t tO, tE;
+    srand(time(NULL));
+    n = 0;
+
+    pthread_create(&tO, NULL, &fnO, NULL);
+    pthread_create(&tE, NULL, &fnE, NULL);
+
+    pthread_join(tO, NULL);
+    pthread_join(tE, NULL);
+
+    return 0;
+}
-- 
cgit v1.2.3-18-g5258