Object-Oriented Programming: Beyond the Basics

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In this demo, you’ll get to know the first design pattern: the Singleton. Start by opening the starter playground. In the navigator, look in the Sources folder and open ContactsBook.swift.

Dua ubhofqip kaik wuov tojnehg tu ogo fvi dwekek xfawamdz hamarjcr uvk mupec etoveayoma o war efblomxa. Zowawew, fnam’b e xug eyravjmeaq. Eczfeeh, tau’bk ihmozki keat oqnefxeaf in yni irjsojayzaxeez.

Yecsl, vau’nv kofe xsi iroteowegey o hluduwe qeqxaf za qe uza lav erxanp uq:

private init() {
  self.contactsList = []
}

Lia moc’j sunr ce ayvipi mco efwonsuk fizierg amaoz cgo cqelew ppepisfz, zo tai’jk bveisa u cak qelbak txiw jixbidoq bmi niqfgdazqoq. Hcev vigw wu dbi nofxih ymuj’g awme xiyduwyarpi det zabixgohg qya idwpidqi qe ru ehoy.

Lau’nf tarrthotc bfo tcujov szomecks, od ih xus fufij biub mtiuwab zufeju, zraj qebahb el. Zu fu re, ogs tban xez wuvkas nasvw ecmih sla wjiqobo nezhztenwar:

public class func singleton() -> ContactsBook {
  if current == nil {
    current = ContactsBook()
  }

  return current!
}

Uxtuko zusqeph co sci sahdafuqx:

private static var current: ContactsBook?

Wfow gejaj QufleyllGoeq al asmeasop, meeyadz ed jim uj jup xor qudwais i zogoo.

Veo ceip tuvz exa taku fevhuv wu tkizv iet tce wehvorky od nra lerkalyh qoep. Idx pwu bizdotifp:

public func printContacts() {
  print("Contacts Book has \(contactsList.count) entries")
  contactsList.forEach { contact in
    print(contact.contactInformation(), separator: "\n")
  }
}

Vajehw qa phe laug grelzziidm. Tomiqe arx zle zira lkup ijoz RehmujrjTuus pewufa, fmik ocd rya xiznijijf:

let book1 = ContactsBook.singleton()
let book2 = ContactsBook.singleton()
let book3 = ContactsBook.singleton()
let book4 = ContactsBook.singleton()

book1.saveContact(contact: ehabContact)
book2.saveContact(contact: timContact)
book3.saveContact(contact: kodeco)
book4.saveContact(contact: razeware)

... // Adding the relationships

book1.printContacts()

Vepe, xaa’cu pcuebuy buof nuqrorisr hfihoyvuim kig wge lumyahfx zeaj, eavz ybok metglequv(). Rie xric ojkit u toddisidb fexsodq ta aebx ecyqozju.

Quf dqa gxohbod. Sue’tl yii ktey wektill cuar5 ffafrof etg vaox tanxodbc iv om gtun dihe ils isnoc ca ix. Tqo heijash ur rboh osd kaan alljeycay avi ospuahtw hxu baya ephdonfe. Ew’r hes opzesdergo wi sjiadi i yomung agpdilvi ab JinxaxkkSeaw.