revise ringbuffer

pa3.c

@@ -204,8 +204,7 @@ struct mutex full;
 void enqueue_into_ringbuffer(int value){
 	acquire_mutex(&full);
 	acquire_mutex(&mutexs);
-	ringbuffer.slots[ringbuffer.in]=value;
-	ringbuffer.in=(ringbuffer.in+1)%ringbuffer.nr_slots;
+	ringbuffer.slots[(ringbuffer.in++)%ringbuffer.nr_slots]=value;
 	release_mutex(&mutexs);
 	release_mutex(&empty);
 }
@@ -224,8 +223,7 @@ int dequeue_from_ringbuffer(void)
 {
 	acquire_mutex(&empty);
 	acquire_mutex(&mutexs);
-	int data=ringbuffer.slots[ringbuffer.out];
-	ringbuffer.out=(ringbuffer.out + 1)%ringbuffer.nr_slots;
+	int data=ringbuffer.slots[(ringbuffer.out++)%ringbuffer.nr_slots];
 	release_mutex(&mutexs);
 	release_mutex(&full);
 	return data;