2

exp1/badcount.c

@@ -4,44 +4,46 @@
 #include <stdlib.h>
 #include <unistd.h>
 
-
 void *increase(void *vargp);
 void *decrease(void *vargp);
 int cnt = 0;
 
-
-int main(int argc, char **argv)
+int main()
 {
     unsigned int niters;
-    pthread_t t1,t2;
-    
-    if (argc != 2)
+    pthread_t t1, t2;
+
+    niters = 10;
+
+    for (int i = 0; i < 10; i++)
     {
-        printf("Usage: %s <niters>\n", argv[0]);
-        exit(2);
-    }
-    niters = atoll(argv[1]);
-    
-    pthread_create(&t1,NULL,increase,(void *)niters);
-    pthread_create(&t2,NULL,decrease,(void *)niters);
-    pthread_join(t1,NULL);
-    pthread_join(t2,NULL);
-    
-    if (cnt != 0)
-    {
-        printf("Error! cnt=%d\n", cnt);
-    }
-    else
-    {
-        printf("Correct! cnt=%d\n", cnt);
+        printf("niters=%d\n", niters);
+        for (int j = 0; j < 20; j++)
+        {
+            pthread_create(&t1, NULL, increase, (void *)niters);
+            pthread_create(&t2, NULL, decrease, (void *)niters);
+            pthread_join(t1, NULL);
+            pthread_join(t2, NULL);
+
+            if (cnt != 0)
+            {
+                printf("Error! cnt=%d\n", cnt);
+                exit(1);
+            }
+            else
+            {
+                printf("Correct! cnt=%d\n", cnt);
+            }
+        }
+        niters *= 10;
     }
     exit(0);
 }
 
 void *increase(void *vargp)
 {
-    unsigned i ,niters = (unsigned int)vargp;
-    for ( i = 0; i < niters; i++)
+    unsigned i, niters = (unsigned int)vargp;
+    for (i = 0; i < niters; i++)
     {
         cnt++;
     }
@@ -51,7 +53,7 @@ void *increase(void *vargp)
 void *decrease(void *vargp)
 {
     unsigned i, niters = (unsigned int)vargp;
-    for ( i = 0; i < niters; i++)
+    for (i = 0; i < niters; i++)
     {
         cnt--;
     }