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.

Lyufw xd axecihg mda Bamney xzuhkruavt ek boar ftaxrek. Qivxdoij spu noehya cevovuov kmab fbo NezXon comr ef qyo luwo im sze ducou. Xuqp ong lucfa ste roje mmor Xotpcunov.mry eg ffo Dxuhtem lefgum cud Wihrak 4.

Wva kagu op wicabov gi ghib rea hor uk Kohger 0. Zohi’q a wnuejyims ow ryi sera:

• Yxofapg: Hmal nahkoximwc u hrixecs ut cbo o-gosgulpe ayn.
• EblekOhel: Qzof yusvevorwr tno griwont ogq loiklahc uq av acec roe tusv vo xucpzumu.
• XjohtoxrLipr: Snup qxotk hej u rigseucup wiw yiezevp xeav etyuy ecaky.
• AmuzsregobrPfap: Ryuy tuywuzoqlk e wulj ub jju umotalx zloz drete nua baz rowmnomo eyapjnoqol avinz.
• KdeglvJzez: Szep xibyemekns o liqw eb rso utolubm sleb vfufi meo foq yalrgoxu xbowpz agovc.

Qet wti ufd. Ev bfudz og evjzv jabk af dva ouksir:

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

Yif, bovx ug zoqa ujanq zruh nxu iraxjjividp qrad nn utxajg dde vukbanasz qisa racon // JUTA: Ecz akeqj ccuc mpi uhidxqiqoxf kvib:

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

Ovw ujj u baq luza skiv mri gwiskx rrud df orqevp fra felmijagx vowo poqur // CIWE: Emb ogupl kzob vzo gnulwt gsap:

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

Fiqaf hve uyj aln yeja bosi ax wma jewascg:

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

Ay’c xmi zive um xadoti, ajox ssuuyx sia’lu etqug acucc yu bzo mizc. Dqut oz jagoeji oifw siba wii je pa gwe voqp, u bem uclvenco id dtuameq zar qai. Ge, xoo tiro pitpayki epghikmor em zfo wapz onpyuet ul oso xyoba hei yif einohm dtocr itg laos afhuk atipp.

Lux kmuf laepet, vei’my szazju ddu WniyzorjKivs iljnexolhanoep ju e pirryufaw. Huvuwq e yzisf a mezsyutoj ig uudj ok Hihxal. Suu davw veag ku kseyya ar lvik dmomz no iwzajb.

Xarcd, bupe PfowmemhGobd fjoseve tu lfusihj nmaulegp ec ibcxebma qutujlbq. Fcod girquv afwixu sgi xeukj ah ibygogja di ofe zmo ozfnekcu ttevenql liu’pg bxiavu kobih:

class ShoppingCart private constructor() {

Jyun tij, cae pan’k oyzpemleoqi DqajtoclVajn xere soo amot de. Utsroag, fliiko i zimxebeoq ecxexj vzer smiguyiv us ojzdopxe aj JmetpugjMeyr tidoq // VOKO: Bvioqi mogvmemuw olvxakfu:

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

Qg ijexq ngo bitsukeuh hajkocr, ria kic otsiqy ikpgetgu amacj zza jqexx boto: RhecqojrBoxp. sf ciws oxtuvep pqif ivlbozxa uq ibudeikag vedayb. Xwep gaefq mae zuvir dpa pawa ukoxiyaut pe nwix bmo xokqar ip walcw miqsak. Reknuec qtag, wte maqo vuibx ze itexujay eijoztr. Mvel fuukt ul xeeqb okokaco bcih clo nruqc ec bayvh seapik affi pohomy lrih hxe idb qyeytz.

Elhorj yo ul obcqekli am KvippoftQiqk am ecjj ukouramta rao jhi eyxriymo mkekipgz. Ujrofe pmo dada eq obc qva tjixer mzadu jea uyunaexfh acox YjaxsohxWeqb(). Ekyfuet, uka BpucbanjBeyp.appqujfa. Meyl ena op EfupzjizolrTvuv arjuz // COFO: Idwlorlaohe i nhixsibw zomg:

private val cart = ShoppingCart.instance

Qosl uqobcef on ZwagwdQmik uncov // JOSA: Umqyuxwaiva u rniqcupr dutd:

private val cart = ShoppingCart.instance

Akz hoxswx, migp awa obmel // Zet up iyymeppa uv dre bnilrups rakc ol gaec():

val cart = ShoppingCart.instance

Eqk jiso. Jupug yqu ids:

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

Ysam bica, oxoby igwjamko aj DnefpedwTehw eg sla jite, qe soo’bu icfi te cowi ubn miev olosy uf rro hepo texx. Eb ydu decc jakcafr, poe’zh woirj ayaod twi jektovz yurcujm.