@H_502_1@

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,factory: String) {

        self.factory = factory

        super.init(name: name,age: age)

    }

}

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",factory: "钢厂")

let worker2 = Worker(name: "Ben",age: 20,factory: "电厂")

 

let people = [student1,student2,student3,worker1,worker2]

 

for item in people { 

    

    if let student = item as? Student {   

        print("Student school: \(Student.school)") 

    } else if let worker = item as? Worker {      

        print("Worker factory: \(Worker.factory)") 

    }    

}

...

let people = [student1,worker2]

...

let stud1 = people[0] as? Student    //people数组的第一个元素

print(stud1)

print(stud1!.name)

 

let stud2 = people[1] as! Student    //people数组的第二个元素

print(stud2)

print(stud2.name)

@H_502_1@