fix：for -> for-in

2021-06-23 00:04:12 +08:00
1 changed files with 1 additions and 1 deletions
--- a/source/02_language_guide/16_Optional_Chaining.md
+++ b/source/02_language_guide/16_Optional_Chaining.md
@ -97,7 +97,7 @@ class Person {
 ```swift
 class Residence {
-    var rooms: [Room] = []
+    var rooms = [Room]()
    var numberOfRooms: Int {
        return rooms.count
    }