标签：swift swift教程 swift视频 ios ios8
继承会发生在子类和父类中，如图所示，是一系列类的继承关系类图，Person是类层次结构中的根类，Student是Person的直接子类，Worker是Person的直接子类。class Person {
var name : String
var age : Int
func description() -> String {
return "\(name) 年龄是: \(age)"
}
convenience init () {
self.init(name: "Tony")
self.age = 18
}
convenience init (name : String) {
self.init(name: name, age: 18)
}
init (name : String, age : Int) {
self.name = name
self.age = age
}
}
class Student : Person {
var school : String
init (name : String, age : Int, school : String) {
self.school = school
super.init(name : name, age : age)
}
}
class Worker : Person {
var factory : String
init (name : String, age : Int, factory : String) {
self.factory = factory
super.init(name : name, age : age)
}
}
let Student1 = Student(name : "Tom", age : 18, school : "清华大学") ①
let Student2 = Student(name : "Ben", age : 28, school : "北京大学")
let Student3 = Student(name : "Tony", age : 38, school : "香港大学") ②
let Worker1 = Worker(name : "Tom", age : 18, factory : "钢厂") ③
let Worker2 = Worker(name : "Ben", age : 20, factory : "电厂") ④
let people = [Student1, Student2, Student3, Worker1, Worker2] ⑤
var StudentCount = 0
var WorkerCount = 0
for item in people { ⑥
if item is Worker { ⑦
++WorkerCount
} else if item is Student { ⑧
++StudentCount
}
}
println("工人人数：\(WorkerCount) ，学生人数：\(StudentCount) 。")
let Student1 = Student(name : "Tom", age : 18, school : "清华大学") ①
let Student2 = Student(name : "Ben", age : 28, school : "北京大学")
let Student3 = Student(name : "Tony", age : 38, school : "香港大学") ②
let Worker1 = Worker(name : "Tom", age : 18, factory : "钢厂") ③
let Worker2 = Worker(name : "Ben", age : 20, factory : "电厂") ④
let people = [Student1, Student2, Student3, Worker1, Worker2] ⑤
for item in people { ⑥
if let Student = item as? Student { ⑦
println("Student school: \(Student.school)") ⑧
} else if let Worker = item as? Worker { ⑨
println("Worker factory: \(Worker.factory)") ⑩
}
}let Student1 = Student(name : "Tom", age : 18, school : "清华大学")
let Student2 = Student(name : "Ben", age : 28, school : "北京大学")
let Student3 = Student(name : "Tony", age : 38, school : "香港大学")
let Worker1 = Worker(name : "Tom", age : 18, factory : "钢厂")
let Worker2 = Worker(name : "Ben", age : 20, factory : "电厂")
let people1: [Person] = [Student1, Student2, Student3, Worker1, Worker2] ①
let people2: [AnyObject] = [Student1, Student2, Student3, Worker1, Worker2] ②
let people3: [Any] = [Student1, Student2, Student3, Worker1, Worker2] ③
for item in people3 { ④
if let Student = item as? Student {
println("Student school: \(Student.school)")
} else if let Worker = item as? Worker {
println("Worker factory: \(Worker.factory)")
}
}这3种类型的数组都可以成功放入5个实例，而且可以在第④行使用for Int循环遍历出来，其他的类型代码不再解释。
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标签：swift swift教程 swift视频 ios ios8
原文地址：http://blog.csdn.net/tonny_guan/article/details/39057283
