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>> DAVID J. Malan: As you know probabbilment,
temperaturi jitkejlu bl-użu

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skali differenti fi Stati
partijiet tad-dinja.

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Per eżempju, 212 grad Fahrenheit huwa
100 gradi Celsius u 32 grad

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Fahrenheit huwa 0 gradi Celsius.

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Ma Ikun sbieħ jekk kellna kompjuter
programm li ħallietna nsiru

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jikkonvertu minn, ngħidu aħna, Fahrenheit
biex Celsius?

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>> Well, nistgħu jiktbu dak il-programm.

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Ejja ewwel tibda bil jinkludu cs50.h,
sabiex inkunu jistgħu jużaw funzjoni msejħa

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tikseb float, li, bħal get int, gets
numru mill-utent, iżda din id-darba

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floating point numru - wieħed
ma 'punt deċimali.

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>> Ejja jinkludu wkoll io.h standard
sabiex ikollna aċċess għal

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funzjonijiet simili stampati f.

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U ejja wkoll jiddikjara prinċipali
bil-mod normali.

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>> Ejja jmiss fil-pront l-utent għall-
temperatura fil Fahrenheit.

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Ejja issa fil-fatt tikseb dik it-temperatura
mill-utent, l-ewwel billi

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tiddikjara varjabbli imsejjaħ
f ta float tip.

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A float, għal darb'oħra, li jfisser varjabbli li
Taħżen valur b'punt li jvarja,

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wieħed ma 'punt deċimali.

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>> Ejja tassenja din ir-ritorn
valur tal get float.

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U mbagħad ejja jagħmlu daqsxejn ta 'aritmetika
fuqha, l-ewwel tiddikjara float ieħor

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sejjaħ C għal Celsius u jaħżen fil C tal-
riżultat ta 'xi aritmetika komuni.

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5.0 diviż bil-9.0 drabi F minus 32.0.

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>> Ejja issa jistampaw il-riżultat
ta 'din il-komputazzjoni.

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mija f -

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li jfisser placeholder għal
floating punt valur -

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comma C biex jistampa l-
temperatura Celsius.

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Ejja tiffranka finali tiegħi.

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Jikkompilaw mal F għall C. Mexxi l-programm
ma dot slash F biex C.

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>> U ejja jippruvaw dawk komuni
temperaturi.

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212 gradi fil Fahrenheit
huwa 100 grad Celsius.

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32 gradi fil Fahrenheit huwa
0 gradi fil Celsius.

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>> Issa tikri tirfina dan il-programm ftit
bit billi ma istampar pjuttost ħafna ta '0

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wara li post deċimali.

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Biex tagħmel dan, jien ser
jmorru lura għal-linja 11.

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U aktar milli biss tispeċifika mija f,
Jien ser minflok tispeċifika, ngħidu aħna,

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0.1 f, tinforma print f dak I biss
tixtieq li jistampaw valur b'punt li jvarja

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għall-valur wieħed wara l-punt deċimali.

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>> Ejja resave-programm tiegħi.

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Recompile ma make F li C. Imbagħad
terġa 'ssir bl dot slash F biex C. U

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ejja retry ma ', ngħidu aħna, 212,
li tagħti me 100.0.

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>> Issa huwa min jinnota li għamilt
xi ħaġa very deliberatament fil-linja 9.

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Avviż kif I kiteb 5 huwa 5.0, 9
bħala 9.0, u anke 32 bħala 32.0.

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Ukoll, l-ewwel tnejn ta 'dawk il-valuri kienu
ħafna deliberatament magħżula bħala

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Valuri b'punt li jvarja, mhux biss għax
ta 'konsistenza mal-bqija

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tal-programm tiegħi -

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li b'mod ċar tinvolvi f'wiċċ l-ilma
punt valuri -

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iżda minħabba jirriżulta li C, Jekk inti
jaqsam l-int minn int ieħor, il-

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tweġiba jirriżultaw int ser tikseb hija
innifsu int, anki jekk dak il-mezz

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jkollhom armih kollox
wara l-punt deċimali.

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>> Fi kliem ieħor, jekk nibdel dan 5.0 sa
5 jew din 9.0-9 u mbagħad resave

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programm tiegħi, recompile bil make F sa C,
u mbagħad jerġa 'run ma dot slash F

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li C u t-tip fl-input ta 'prodotti simili 212,
avviż li r-risposta jien ser

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nikseb dan iż-żmien huwa attwalment pjuttost ħażin.

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0.0 mhuwiex il-grad korrett fil-
Celsius bħala 212 Fahrenheit.

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>> Well, x'inhu għaddej?

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Ukoll, f'konformità 9, minħabba 5 issa hija
integer u minħabba 9 issa huwa

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numru sħiħ, ir-riżultat matematikament
għandha tkun 0.5555 u l-bqija.

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Iżda minħabba r-riżultat, skond
Regoli Ċ, għandu jkun hemm int, li

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0.5555 gets tintrema,
jħallu lilna biss 0.

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>> Għalhekk fl-aħħar, I jispiċċaw multiplikazzjoni
pjuttost aċċidentalment 0 darbiet f minus

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32.0, li huwa irrelevanti x'inhu
dejjem ser jagħti me 0.

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Allura wieħed iżomm f'moħħu, kwalunkwe ħin jużaw
Valuri b'punt li jvarja fil-viċinanza ta '

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ints, inti tista 'ma neċessarjament
jiksbu l-risposta sabiex inti tistenna.

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U sabiex jieħdu ħsieb għall-użu, kif għamilt fil-
Valuri ewwel każ, b'punt li jvarja

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madwar biex jevitaw xi kwistjonijiet bħal dawn.

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