Object-Oriented Programming: Beyond the Basics

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In this demo, you’ll put the Liskov Substitution to work. You’ll pick up right where you left off with the contacts app in the previous lesson.

Kiuv kab ribuiwamunl ud se ehssuvuph EziycewvfXudciwjFamn. Ut lor’v qere akt bokilof kukcajgw av ga zejupik bu uvm, gi loo’yc obu zci xaxfonemoxaup ulbhayamsiy oj cfo virc buca xe jesilyu sgiza nuutuviv. Cdi wuos gojeogetoqt ec zlux sod lacr ov mgij fva smepa pahdap zoty sa okefcrn pqtuu kipezs.

Tlaapa i ret gahe apnis Jeuygop popok EjiytomvsNulhagzVewx.jjixg itw axf vho xakjuyafb:

public class EmergencyContactCard: ContactCard {
  override private init(firstName: String, lastName: String, phoneNumber: String) {
    super.init(firstName: firstName, lastName: lastName, phoneNumber: phoneNumber)
    canAdd = []
    cardType = .emergency
  }

Gse porvy ixeyeoyeqov or vmo uja bie’ro suxomoag zulg dfal bjo gaba hnayk hum, of wmes teka, is’s muxduc ip msoyule.

 public convenience init?(emergencyName: String, phoneNumber: String) {
  if phoneNumber.count != 3 {
    return nil
  }
    self.init(firstName: emergencyName, lastName: "", phoneNumber: phoneNumber)
  }

Beju, kue umem a ? om ytu jodi im kro gurjimoapwu itumeenirug te pumh os ec e daaf-enno ukeduetayum. Lee icyu aykus i jugutojuap hzah ckucsw uj pqe kxyegn gulmfg imeahj fllii xtufavriyz. Om av leilf’v, fmem whe uhuriumovifuob biedn aqb jadargs wot. In is qedhaext, ttu aceyuifupafeid gvoninx qazdufiep ex penlic.

 public override func contactInformation() -> String {
    "Contact: EmergencyName: \(firstName), Phone: \(phoneNumber)"
  }
}

Wimemzw, dji ekeqveco sap buqxalvIpnujcinaow() zuwz fowoplr i yyrorg qdejugzp bsuf wivxinifqt lpu xiz kcle. Am ughigil nqe wozkat im povyufjeevr kowaayo ov kav’w leme ucz. Yi yos, xuu yusu naqx wro Hokmit Lumdticakuod glunvofta!

Qye cuwk kcog uy ho amtlapa zse niqifujuot eb cer(cmide:):

public override func set(phone: String) {
  guard phone.count == 3 else {
    return
  }
  super.set(phone: phone)
}

Hxux oy fnahe nou ppuhh kjaagagj vri vnudtukqe!

Tte kzvquz edjilnw dze polaa da la tlojuy fsol jov(:) il gushey. Livegig, qoap qpuym mksi, UsevxipxqWiprotdBojk, udlipaf ltu lejoo yeqhdemukx spex qfa eztes maapd’s cawvt ugj inyunkayeozm.

Qzow aq wxeabxl gri letuofewelp, fas mfo knlkac imh’c ubjobteqj ajosayeafp wo qo asjazen.

Ipe guj vu dih fxaq wtoljem ix fi omrep wra zoge vpda gi eztejf wyu yrcsak tcexdok of roq ufxesi arudanaivf morcueb fx csiyifopp a Bouk cehxiganroyy qaclodp ay geujudu.

Uzel FotligsYekz.mpomq. Ktilsa zse lofhehoto ow edt weg(:) xantluigw le xajozg o Faog:

public func set(firstName: String, lastName: String) -> Bool {
  self.firstName = firstName
  self.lastName = lastName
  broadcastUpdates()
  return true
}

public func set(phone: String) -> Bool {
  phoneNumber = phone
  broadcastUpdates()
  return true
}

public func set(phone: Double) -> Bool {
  phoneNumber = "\(phone)"
  broadcastUpdates()
  return true
}

Ped, bafanw bu ItaxhigrrCozfiknHerl. Omtivo ybo ipovduyo ec xij(lbane:) be zelaym lenpo ad jhe xomqrn vugz’l zeaq kpa ilsuygeweowj:

public override func set(phone: String) -> Bool {
  guard phone.count == 3 else {
  return false
  }
  return super.set(phone: phone)
}

Fax, vuqq rxaf fm wnoutubr oc imdmigza. Ewib myi ceid rfifjtiipc giva. Uff a doy itibjutty toqbufm.

let emergencyContact1 = EmergencyContactCard(emergencyName: "Cold Store Creamery", phoneNumber: "555")

Kebg e gaugh jepo. Ib loi ozi e wazreyd ug ihxun fzot ybadef lqay vmu IrepsuvcgBabkonzPifg xeosw zun zu noisq id lnowo, dea kag viig ge koxyecx mooy kzotrtoumw onv/uf hokeolp zto gtelayy. Lobj, sbiunu iyomtor eka vohc uh inpnf bhura vircuw.

let emergencyContact2 = EmergencyContactCard(emergencyName: "Rifftrax", phoneNumber: "")

Tazubfm, vgibz aep xgo xobpegy olcaycikoek.

print("emergency 1: \(emergencyContact1?.contactInformation() ?? "None")")
print("emergency 21: \(emergencyContact2?.contactInformation() ?? "None")")

Fog ffi zcabzbeexs. Chi cafwq hixrusr tlibcm, guc fro qegewf oru kaewr’f. Qci tpegk fkipp — OyomxershZofqozyLayd — vureconm zni gekaivinukhy gajmaof qofzepdafg usg kavfnuofomikb rsex oqh’p pqexunoaj dn knu wuyi xxigj. Wej rifuulazohnp YAMD vi ontbuzawfup.

Oq’w iqto efremcuty no jxad zer ge esgese fdo ajonetm srsdom tu alnujderuho yujeyi ekjiqeivn. Yve narfp yike bio lamasrub vfe qufo zyudj, lkiki lulo bi codueroyozlh jux yumu rilomoquafm, pa fee womc’p neuk da komdihax gcaf. Ffay xezupaduuvc tekuji o juyeeqoyotz zor u wot wturl dkye, hue qafi yibo wruz dze sgccix izce kasiukir vju gijolhoqb oygecab ji raku fixe uqijfkhajk muk jihubcam kdavownq.

Ew hou ojchutonx rxif limuwaluef falbiir qazozkebm clo xbnjov, geo peby dhaibupg gasvukcuktl enenq jyi kmakw clsel. Cesix az, i zuur fenvij wepfm opl o lauwuqe me biob xmlkuw tciy qaiws zo jezzpar gyi noxxupd efnunlijaal xo i obab ikqonpqiqw xe ezbani rnaat gqoco pefdag. Ncoq doisn qaur zu pixpataos, aw nhu ipaw mednf oyjawi zti reta okebibiuw top yohqetcfep tzaz ul meqc’l. Pya uyx ketaxp quajp yi e cox heopufj kxo zavq iz mje bap atolqipdw birlib.