Person

Person.swift

class Person {
    var name: String

    init(name: String) {
        self.name = name
    }
    func printMyName() { fatalError("Error here 😈") }
    func printMyAge(age: Int) { }
}

class MainController: Person {
    override func printMyAge(age: Int) {
        print(age)
    }
}

let mainControllerInstance = MainController(name: "Alperen")
mainControllerInstance.printMyAge(age: 21)
print(mainControllerInstance.name)
mainControllerInstance.printMyName()