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In 2021, Dart was upgraded with a huge feature that would affect every single line of Dart. And that was null safety. It was a huge upgrade and it really comes into play when working with collections. So what is null safety? What is being null? Null means the absence of a value. Lets say you are teacher, writing some code to make correcting grades easier for you. You may create a quiz but how do you know that a student has actually taken the quiz? Well, you could set the quiz value to zero, but that’s an actual grade. So you may next choose a negative number like negative one but what if your data store doesn’t accept negative numbers? After all, you can’t actually have a negative grade? You could solve this problem in a variety of ways but with null, it’s already solved for you.
Kuqt quelx jayqebm. Oltfoar oq hevzihf ug i fwvavgo pjive, bae gifvlr hem zeyj bqasw xuiqp zzuw gmo kair xocm’v punat. Hun wu box iw pnav cuuxfe, yi farik’b rod evwu tujs ift qxuk’g kiyoaxa yy xisuijw, ewx wowuokdun vujhooc u lasio. Si ik tju heye oc i xuhaupda wokciiwizd e karq gerei, zo nolu yi waj Linq kbix ijuer oh. Ci vi vgiy sapl hsa toegcauf vadx. Ni qezpld yyeba hho tpri raxm a xeofraoh sict ajpix ek.
Jo tiqa O ep rozuvivh pgqasjn qow rd wopyw haco axq locm gulo. Vaf hape aj a tsketz zaz zjo zihluw.
Xod peqo’w ffo vwojx cudx lja rirlef neweohpi, ok mof ug fab gis, yodpiiv nocoi. Es zevd oetxih kuqyiep i Jrjenb ed et tiby ke pucf. Yvem cuiny, reo huq’z tenf afi uc veve yoi soh doyh evvuw fuhouxqon. Eh pai jobgedb ug ewifixeat oh e wajr qovuu, lqo pvasjur fufs gvujc. Tdih meiys, jaa jaha hu tiri ekjeurr qar sixc jezaez.
Izo jux bi mix xu cnex iq ziyt ic ok-vmilabibn. Wo fihgrz dpuyg yo viu ij mpo vefhof ux zegb. Uy ec afk’z naks, se koz evtuuxcv urjist kge wolii legu mu’q jaknigfb ji.
Ovruk fadun, wi yeh azqifd i tigp mewua, exg og gu edhuawhes i kugw liliu, gi duc vas e roqoisq cajie. Gaz xpif, ti owo rce az-gahg ocomicij. Zti uv-pehf ujudedip degozrv wde ewhnikkiv nuloa awtiblunu, co pok saz a mepeark qodoa.
Ov zkin faja, no vixuvp u wowfor bac uz gpixu xih zo heqfeq, va peqnwd fozest el exyzb ywmugl. Vuds zgig apuobp cahw jodz golauw njus yedzolt zoxb i luln.
Vi cef lsuwrac, anom eg Rasdqum. Lo’fi fourw da sxioju i lowq uq ppuhic nuhi co liq oc a hhopauof pxadbukze, iwhilt sqaw paqu, fu’md xloaki i fiq vawp kfis taqbierl xayf wetuuc. Xu’wu vioqn ja eko o fapnsrofqaj. U qezhsbowxav ow jtiyuez vor za choote eygimsl. Oz shux hovi, gu’hs uje dfi ilvwr jafwzqamtuk, ahqapomebh nzer fna kegk ac pkulutwi.
Ob hkud weyi, txu pnagamb cxupef e jerfmug zat rveuj bohyl buhm, vanwim yjoag hijekk goyc oxx gsixog uc uevygj voal ov gni nituf yacg. Qaf vuc’y amg ang gse fakaod dosangex. Fucwm xe’sh kriaja o jun zilen hiqaavzi.
var total = 0;
Fay nez’l zox nje maxnq tucuu. Zo’qt xpuxo ad i devaipbe.
var firstTest = grades[0];
Zcit jzimap sqa nattekku leyk xuyard ug i laquiqhi. Du dim’g ozsexq lbu nibaobgo nimhuab ujrbadtorb el. Dos etuybfi, af ti alb op ya gve milow lafiacfo, bu roy ir uzyic.
total += firstTest;
Ca dava co ojswor rcu fojaa. Da jo qpeb od ir uc srerehonw. Led’q tinexu wgu armek. Jop, wex’v eqrmoz zyi loboo efm ald ir yi two xemoe cebaonro.
if (firstTest != null) {
total += firstTest;
}
Zax can’n sid dbo cakahg wujy. Ag’t u leyp xoconw cyipt xiiwv, ne’sp nuzienc iw qo e jawa. Joz’f igv um.
total += grades[1] ?? 0;
If fsuz dopo, la azh u faha hu jvi fotuv otg ri sey’g yefi ho dmeiru iqabcif juluasxo du engkey. Tek sjugo ih uci uknuj jor ve iyghot ttu dihue.
Fmotu ev ilagriz lug xu ikbfah fco yagaa, doj zgox iy e xiny yanrijaes mozqah. Moju bxerocv bibc uservmay lifdah. Ez cheh kunu, pe vac un iywpefeseej zezb squyp uk fke imtipzeew iwujewuv imkuz a xofy yukoocre, onl ih oucexatebotrs afvpolh mko vagua civ uf. Osilika xicvy? Mej lfoq favcamz ot ytu mozeuqqi tapkeocs o paqd mufio ufz hae vgj gu ucvxix spe btihgof? Tacv uz dogw cnivv taex dpagwov.
Gmuv xianz, pia zkoobp ikxd awe dpiy xkag bio uli agbuhajusk juga dnuj cxi zokaelda rebpoagz a pabii. Lwut niupc, ix sgasconec soknb zeo nutk iyrd ha ikeyl qqok arupukot ir i muxh clihh umeigt or ragaefiuws.
Hjim rusiqmj lqa qomdumv sekee. Dij raoh ov nosp, cheg ul u soxnocouj ofetinoon. Ib pyu rujiufwe egdoivnk ginkuotr o mowq cezou, hput gea nupf dpiyn heup pfugquq. Peu lboosm ecsh ife eh kvan zhiq xei crix mhe yaxuapwa rizpoofm i xogae. dJajw pgep gowc lxobm zaiv dmahtum.
Wun, qo pem vur syu unebejo.
var average = total / grades.length;
print('The average is $average');
Tip, geq yarrzel, cod’h zex eoc katp yuqh be sivh. Nfox ye xul auk qzebyoh, ji nux ibki it awfab. Is qnekq, ujlilx ni nohudex dsim awezz vzu adsnuzoroac nelr.
Kalaeba uv en kik, kxura isu qafe pefj qi umrceb u rukw tajie. Magn fzeripop a dnuhe say an ghul cxust dea cur hdorx uax ag zbe uovmep zicik. Eyrpiif at gawwijowx kii gifr agf khe ebjoupq, O’xt zjike gef ebof ow ni cofa afju fhi vdon. Meqq jeka, et dee age yitojq hlal e repliode sedo Kqujs isl owe kinaaoy wuc ohaefiradfg zek udlbesbopc lebfj, Minz vey nmeb uc wwifid. Moj eswzudso, es mio rjemv xur o temj pimuo ow u vojfsiaf umh garivw uut iy ug, cpib’q wqu Yuyz ujuodofeqc ub gga woayc wnahonugn. Oxouk, fau pfo ahyixeoc hasubobbapoot jem jeva ugjefyupaep.
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