下面看一個示例：
final class Person { //聲明為final，說明它是不能被繼承的
var name: String
final var age: Int //定義的age屬性
final func description() -> String { //定義description實例方法
return "\(name) 年齡是: \(age)"
}
final class func printClass() ->() { //定義printClass靜態方法
print( "Person 打印...")
}
init (name: String, age: Int) {
self.name = name
self.age = age
}
}
class Student: Person { //編譯錯誤
var school: String
convenience init() {
self.init(name: "Tony", age: 18, school: "清華大學")
}
init (name: String, age: Int, school: String) {
self.school = school
super.init(name: name, age: age)
}
override func description() -> String { //編譯錯誤 //試圖重寫description實例方法
print("父類打印 \(super.description())")
return "\(name) 年齡是: \(age), 所在學校: \(school)。"
}
override class func printClass() ->() { //編譯錯誤 //試圖重寫printClass靜態方法
print( "Student 打印...")
}
override var age: Int { //編譯錯誤 //試圖重寫age屬性
get {
return super.age
}
set {
super.age = newValue < 8 ? 8: newValue
}
}
}
定義Student類，並聲明為Person子類時，會報如下編譯錯誤：
