class Person {
var name: String
var home: Apartment?
init(name: String) {
self.name = name
}
}
class Apartment {
var buildingNumber: String
var roomNumber: String
var `guard`: Person?
var owner: Person?
init(dong: String, ho: String) {
buildingNumber = dong
roomNumber = ho
}
}
let yagom: Person? = Person(name: "yagom")
let guardName: String? = _________
정답 :
yagom?.home?.guard?.name
yagom?.home?.guard?.name = "슈퍼맨"
let name = guardName ?? "경비원"
print(name) // [출력결과]
정답 : 경비원
class Person {
var name: String = ""
}
class Student: Person {
var school: String = ""
}
var yagom: Person = Person()
if let casted: Student = yagom ______빈칸________ Student {
print("\(casted.name)은 Student입니다")
}
정답 :
as?
(다운 캐스팅)