Swift Tutorial - Tutorialspoint

Subclass initializer cannot delegate up to the superclass initializer when overriding a
failable superclass initializer with a non-failable subclass initialize.

A non-failable initializer can never delegate to a failable initializer.

The program given below describes the failable and non-failable initializers.

class Planet {

var name: String

init(name: String) {

self.name = name

}

convenience init() {

self.init(name: "[No Planets]")

}

}

let plName = Planet(name: "Mercury")

println("Planet name is: \(plName.name)")

let noplName = Planet()

println("No Planets like that: \(noplName.name)")

class planets: Planet {

var count: Int

init(name: String, count: Int) {

self.count = count

super.init(name: name)

}

override convenience init(name: String) {

self.init(name: name, count: 1 )

}

}

When we run the above program using playground, we get the following result: