diff --git a/hashtable.c b/hashtable.c
index 24ce993..c651fdb 100644
--- a/hashtable.c
+++ b/hashtable.c
@@ -12,7 +12,7 @@
 struct entry
 {
 	const char *key;
-  void *value;
+	void *value;
 	struct entry *next;
 };
 
@@ -99,7 +99,7 @@ void *hashtable_set(hashtable h, const char *key, void *value)
 	}
 	// found replace the value
 	void *old_value = item.found->value;
-	item.found-> value = value;
+	item.found->value = value;
 
 	return old_value;
 }
@@ -120,36 +120,37 @@ void *hashtable_remove(hashtable h, const char *key)
 		return NULL;
 	}
 	// found, so detete it
-  if (item.prev != NULL) {
-  	item.prev->next = item.found->next;
-  } else {
-  	h->table[item.index] = item.found->next;
-  }
-  // free unused memory
-  void *value = item.found->value; // remember value
-  free((void*) item.found->key); // free key
-  free((void*) item.found); // free entry
+	if (item.prev != NULL) {
+		item.prev->next = item.found->next;
+	} else {
+		h->table[item.index] = item.found->next;
+	}
+	// free unused memory
+	void *value = item.found->value; // remember value
+	free((void*) item.found->key); // free key
+	free((void*) item.found); // free entry
 
-  return value;
+	return value;
 }
 
 void hashtable_destroy_bucket(hashtable h, int i)
 {
 	struct entry *e = h->table[i];
 	while (e != NULL) {
+		struct entry *next = e->next;
 		free((void*)e->key);
-		e = e->next;
 		free(e);
+		e = next;
 	}
 }
 
 void hashtable_destroy(hashtable h)
 {
-	if (h==NULL) return;
+	if (h == NULL) return;
 	for (int i = 0; i < h->size; i++) {
 		hashtable_destroy_bucket(h, i);
 	}
-	free (h->table);
+	free(h->table);
 	free(h);
 }
 
@@ -158,7 +159,7 @@ ht_iterator hashtable_iter(hashtable h)
 	ht_iterator iter = {
 		.h = h,
 		.index = -1,
-	  .entry = NULL,
+		.entry = NULL,
 	};
 
 	return iter;
@@ -171,12 +172,15 @@ bool ht_iter_next(ht_iterator *iter)
 	}
 	hashtable h = iter->h;
 
-	while(true)	{
+	while (true) {
 		if (iter->index >= h->size) {
 			return false;
 		}
 		if (iter->entry == NULL) {
 			iter->index++;
+			if (iter->index >= h->size) {
+				return false;
+			}
 			iter->entry = h->table[iter->index];
 		} else {
 			iter->entry = iter->entry->next;