class Person {

    var firstName: String
    var lastName: String
    var zipCode = 12345

    init(firstName: String, lastName: String) {
        self.firstName = firstName
        self.lastName = lastName
    }

    func greetings() {
        print("Hi, my name is \(firstName) \(lastName)!")
    }
}

class Employee: Person {

    var staffNummer: Int

    init(staffNummer: Int, firstName: String, lastName: String) {

        self.staffNummer = staffNummer

        super.init(firstName: firstName, lastName: lastName)

        zipCode = 12345 //We override to inherited property of the superclass

    }

    func identity() {
        print("First name: \(firstName), Last name \(lastName), Staff Number \(staffNummer)")
    }

    override func greetings() {
        print("Hello, how are you?") //We override the function of the superclass
    }
}

let christine = Employee(staffNummer: 780, firstName: "Christine", lastName: "Mayer")

christine.greetings()
//Output: Hello, how are you?