Person_v4.swift

protocol AgeClasificationProtocol {
    var age: Int { get }
    func agetype() -> String
}

class Person {
    var firstname: String
    var lastname: String
    var age: Int
    
    init(firstname: String, lastname: String) {
        self.firstname = firstname
        self.lastname = lastname
        self.age = 10
    }
}

extension Person: AgeClasificationProtocol {
    
    func fullname() -> String {
        return firstname + " " + lastname
    }
    
    func agetype() -> String {
        switch age {
            case 0...2:
                return "Baby"
            case 2...12:
                return "Child"
            case 13...19:
                return "Teenager"
            case let x where x > 65:
                return "Elderly"
            default:
                return "Normal"
        }
    }
}