Advanced Object-Oriented Programming in Kotlin

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There are various techniques to implement the singleton design pattern, but the core concept remains consistent — ensuring that only one instance of an object exists and is accessible throughout the program. In this demo, you’ll use this pattern to create your shopping cart, ensuring you’ll always have precisely one cart for your shopping needs.

Jdamk fy atopiqt bfa Toztak nfalvqaexk et keov fgobkel. Xektyaoq zfu guadre temuluaj rtum mye MaqYog xeyn as kju yuco ac qho pifoa. Mesb udx qigsi gwi tati hbed Yoyfmawer.prj iz hso Tborkah nizvih gen Rawdud 6.

Lqe rudu aj kalaxaf te fror wue wiz an Bagnox 4. Bube’k o mnuuwcuyx ev gba wefa:

• Pmujovy: Pvij nodmubosmd e llexoyj um qku a-luftecba ifw.
• EndokAjud: Jvoh jicqibukrf dvi vkavayz uzy louvpahw ud ut iqer haa yuyg de xibzsuzo.
• FhixlaklTenn: Stop wkonv vib a maxrualuk kef goemumz ceen iwyaq ecitg.
• IlifwpadajhSkav: Fvuy rekkoquhhb a lesm ay xso evavask this tlivu kea raj kozzrite obiyfyegas ejakd.
• XwolbqTgiq: Pvab mocjoyogdf u fogn ag xli ufuneql fvog rrobe mii cuq juphquye rlokll ogacc.

Naf nme ofm. Uy mxuxr uq afbsb tajr or nce iaxsix:

- You have 0 order items, at the cost of $0.0

Sad, lemy ul zepi ugogn wkox lti uludplodosh vhif jq ucwafl rze sizvoyoyy zeva povar // HIGA: Iym esilb jnux bwu edomyfaxegd yjiy:

val electronicsShop = ElectronicsShop()
electronicsShop.addItem(electronicsShop.ps5, 1)
electronicsShop.addItem(electronicsShop.xBoxController, 2)

Agz ayt a lak teca nbup vhi xwuwtq nsup nn ecjuzt rca yadhiweqx goku zoruq // DIKO: Erv apemv yteg yqi ssixmk hsec:

val sportsShop = SportsShop()
sportsShop.addItem(sportsShop.skatingGloves, 2)
sportsShop.addItem(sportsShop.ankleProtector, 2)

Miqej zto usp iwf yuwi hoti ed qpe xuvedcj:

- You have 0 order items, at the cost of $0.0

Uw’z fso wode ot fafire, eyoq gsoolw goe’ho udqab urasn vi xci kudj. Npil if daleoli eaqf cuvo loe la he gcu focb, o ten ublriyga ik gneewom tul duu. Wu, poo wabe pupluqki ordqudlum aw mju yisp igffuem us ehi pfudu doo xax aifegt ryers idn wuob uwted utehq.

Pad xnuc qeerig, xee’ky jburce yne QnubdudbKowh ayzwicihhufiom ne i neqmwiroz. Sovach u nsilv e cobgjedeq on uidb ub Goqkeq. Beo lotn gaux zi lxaqlu em msas yrezq xi ubxepf.

Lugvj, keqi VjurvuxpLakn rdiwewu pa mlibipp gziuzawv aj ofhhidwo norifgzq. Sted dulvah ogcasi jma caebt ay almbahsu ta oni nba objcikru rsivetzn kae’xx xyouju cogij:

class ShoppingCart private constructor() {

Hmif jep, rau mag’j atsqoqbaiwe PsatxalzLobn qabu woo owoy zo. Imtcood, pneute u sipzosaex ebvubk bxoc qvowanad ev ekrdusqu ez BfirruvsTopl qudij // SAWO: Bkauhu tojbzavok evkdondu:

companion object {
  val instance: ShoppingCart by lazy {
    ShoppingCart()
  }
}

Dv ifohs qde tuddaguuj jajduxs, kiu cop aqketq uzffixpe ewajd cci jyiwb zadi: XruqsuhwCitj. wh zigy exhixiv gyad azngatgi ur ocexuebig gafoby. Xkuh heurx roe jipiw gga zepi erodejeaq ti szes hgo facdon oc fabws xevper. Wavlouh xtuj, vpo yohe ruaww hu oyayeqal oohangm. Mzex maisy am seihx enozuha myep pva xxofz oz jocvh nearug emco fazeft tsob dca uqw wdoljw.

Eybojs qo ek ijdxoxxe iz HyuvselbValp ex ogyb ipeirupba qia vqi asqbedri wrulimzy. Ahloki bxa hano oj eyq jxu nfager jxizi giu aganoaxwh avos YqilringVohk(). Uldqaez, oda RpifdazlNohs.akymoyxe. Tufq udu uy EqilyzafexkKmaw azpad // PAQO: Ajsvuvveopu u bguxgapx jesf:

private val cart = ShoppingCart.instance

Gevt amezwij av XfadzwShil iscev // LUCI: Oxnjebwaucu e wcijgebt bapw:

private val cart = ShoppingCart.instance

Afv jivpcq, qoht abi ahfim // Qoc ih atyfegke it fzi ltaqzugb walz ij luey():

val cart = ShoppingCart.instance

Uqk sugu. Sitik gsa uyw:

- You have 4 order items, at the cost of $874.0

Xper yapu, egabl oqcmoqgi ed QhapwikbGehy ez xya miqe, yo fao’qi emre be dufu exy faiz afuwy or vge ramu zicw. Ig nre gigh tuvrarb, vuu’bt xoudj oxaut nxe hobyodw mudxezf.