SongPoll4.swift

import Foundation

struct Song {
	let title: String
	let length: Float

	func withAddedAdvertisement() -> Song {
		return Song(title: self.title + " plus commercial", length: self.length + 10)
	}
}

let song1 = Song(title: "Aerials", length: 240)
let song2 = song1.withAddedAdvertisement()
print(song2.length)