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[Powered by Google Translate] DAVID J. Malan: Kull dritt.

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Dan huwa CS50, u dan huwa l-aħħar ta 'ġimgħa 2.

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Jekk inti tistenna li tkun bil-ġuħ madwar dan iż-żmien ta 'għada, tkun taf li aħna qed tmur

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biex ilaqqa bħala għada grupp żgħir, il-Ħamis, 01:15.

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Hemm dan il-URL hawn jekk inti tixtieq li RSVP.

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L-ispazju huwa limitat, għalhekk jekk jogħġbok nahfru jekk il-formola tkun mimlija mill-ħin li inti

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timla dan.

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Ieħor URL għalkemm li jistgħu jkunu ta 'interess hija din.

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>> Għalhekk fl biss dwar żmien xahar, il-kors se jkun disponibbli

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l-aktar wiesa 'permezz EDX, li permezz tagħhom folks fuq l-Internet se tkun

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jistgħu jsegwu tul, jinvolvu ruħhom fil-kors pjuttost attiv, fil-fatt.

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Huma ser tkun qed tuża l-Appliance CS50 u CS50 Iddiskuti u ħafna mill-

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diversi għodod ta 'softwer li aħna diġà kienu jużaw dan is-semestru.

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U waħda mill-inizjattivi aħna tixtieq tieħu fuq bħala esperiment din is-sena

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huwa li tara biss kemm kontenut nistgħu jissarraf oħra mitkellma u

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lingwi miktub.

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Mela jekk inti jista 'jkollhom interess li jieħdu sehem f'dan il-proġett, fejn

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aħna se jipprovdu transcripts Ingliż u sottotitoli għall-kors tal-

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lectures u xorts u seminars u sezzjonijiet u simili -

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jekk inti titkellem b'mod mexxej jew ikteb b'mod mexxej xi lingwa oħra, aħna kieku

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imħabba li jidħlu lilek f'dan il-proġett, fejn inti tieħu fuq waħda jew aktar mill-

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videos, li dawn jinbidlu fi f'lingwa li taf pjuttost tajjeb.

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Biex jagħtuk sens ta 'l-interface, hemm dan user interface web-based

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li aħna ser tkun qed tuża li se joħolqu essenzjalment UI bħal dan.

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Dan kien me tagħlim xi Halloween ilu.

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U fuq il-lemin hemm bl-iswed li jmiss ma 'dawn it-timbri żmien,

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int ser tara l-affarijiet varji li ħareġ mill-ħalq tiegħi dik il-ġurnata.

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U allura hawn taħt, inti ser tkun tista 'tittraduċi fis xi lingwa oħra.

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Eżattament dak l-immappjar huwa bejn, f'dan il-każ, l-Ingliż

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u, ngħidu aħna, l-Ispanjol.

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Allura huwa attwalment ħafna faċli għall-utent għodda.

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Tista 'Rewind u veloċi quddiem ħafna mill-ewwel ma shortcuts tal-keyboard.

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Mela jekk inti tixtieq li tieħu sehem f'din l-esperiment u jkollhom kliem tiegħek

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jidher u jinqara minn potenzjalment eluf ta 'folks hemmhekk, jekk jogħġbok tħossok

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ħielsa li tieħu sehem.

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>> Issa wieħed kelma dwar il-kitten mit-Tnejn, lest għandna bagħtet żżejjed

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scary messaġġ.

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Do jirrealizzaw li kif ħinijiet tal-uffiċċju jissuġġerixxu u bħala taqsimiet li jmiss jissuġġerixxu, il-

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disinn tal-kors huwa ferm li l-istudenti jikkollaboraw u

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tkellem jaħdmu permezz settijiet problema u problemi flimkien.

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U verament il-linja biss jaqa 'għal, għal darb'oħra, ix-xogħol inti finalment

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għandha tissottometti għandu jkun tiegħek.

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U dan huwa, pjuttost onestament - fil ħinijiet tal-uffiċċju, huwa totalment normali -

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huwa totalment mistennija, anki - biex chat ma 'xi

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ħbieb jmiss lilek.

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Jekk hu jew hi qed tissara ma 'xi suġġett, u int simili, oh, ukoll let

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nagħtikom idea ta 'xi linja tal-kodiċi li I kiteb.

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Li l-multa.

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Li jiġri.

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U li ħafna jwasslu, naħseb, mal-proċess ta 'tagħlim.

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Fejn il-linja, għal darb'oħra, gets qasmu huwa meta l-kap huwa tip ta 'mmejjel fuq

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hawn għal ftit sekondi wisq jew minuti għal li verament li jkollhom biss

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kien opportunità żblokk għall-ħabib tiegħek.

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U ċertament, meta l-affarijiet nikseb skambjata permezz ta 'email u Dropbox u

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simili, hemm wisq huwa l-linja.

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Allura bil-mezzi kollha, jħossuhom komdi u jħossu mħeġġa biex chat mal-ħbieb

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u klassi dwar psets u aktar.

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U biss jirrealizzaw li dak li inti finalment iressqu għandek verament tkun l-

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prodott tal-ħolqien tiegħek u mhux xi ħadd ieħor.

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>> Għalhekk fl-istess ta 'kreaturi Cuddly, inti tista'

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jafu dan Guy hawn.

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Allura dan huwa movie horrifically Logged minn snin ilu.

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Kulħadd hawn tidher Spaceballs?

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Kull dritt.

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Allura numru tajjeb hawn.

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Allura dan huwa mod wonderfully akkademiku tagħna ta 'introduzzjoni llum finalment

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il-kunċett ta kriptografija.

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U għalhekk waħda mill-problemi ta 'dominju speċifiċi għall pset 2, li se jidħlu

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barra bil-lejl ta 'għada tard, huwa li adsa fis-dinja ta' kriptografija, li

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hija l-arti ta 'encrypting jew scrambling informazzjoni.

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U dan finalment tirrigwarda l-dinja ta 'sigurtà.

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>> Issa sigurtà għal ħafna minna taqa 'fil-forma ta' mekkaniżmi pjuttost mundane.

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Lkoll usernames u passwords.

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U lkoll usernames u passwords ħżiena ħafna, l-aktar probabbli.

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Jekk il-password tiegħek hi l-istess fuq il-websajts multipli, li probabbilment ma

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l-idea aħjar, kif aħna ser jiddiskutu lejn tmiem semestru tal.

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Jekk il-password tiegħek huwa miktub fuq nota twaħħal - mhix ċajta - fuq tiegħek

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monitor, li wisq mhuwiex neċessarjament l-aħjar disinn, iżda pjuttost komuni

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fenomenu.

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U jekk ma tkunx qed tużah kriptografija għall-kriptaġġ passwords tiegħek, huma

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partikolarment vulnerabbli.

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Mela jekk inti taħseb li int qed super għaqlija billi jkun hemm Word moħbija

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dokument x'imkien fuq hard drive tiegħek li tkun kollha ta 'passwords tiegħek imma

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huwa fil-folder li ħadd għaddej biex tħares, li wisq mhuwiex ħafna

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sigura mekkaniżmu.

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U iva, liema pset 2 se jintroduċi hija din l-arti ta 'kriptografija u

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scrambling informazzjoni sabiex affarijiet simili passwords huma

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l-aktar sikuri.

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Sabiex timmotiva din il-problema ħafna tad-dinja reali ma 'ħafna mhux tad-dinja reali

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xenarju, let me jintroduċu inti lil wieħed mill clips favoriti tagħna hawn minn din

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movie, Spaceballs.

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>> [Daqq ta 'video]

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-Elmu, inti fiend, x'inhu għaddej?

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X'Ser tagħmel biex bint tiegħi?

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-Permess me jintroduċu l-brillanti żgħażagħ plastik kirurgu, Dr Philip

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Schlotkin, l-akbar imnieħer impjieg bniedem fil-sħiħ

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univers u Beverly Hills.

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Your-Altezza.

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Impjieg Imnieħer-?

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Ma nifhimx.

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Hija li diġà kellhom xogħol imnieħer.

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Kienet ħelwa 16 preżenti.

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-Nru, mhuwiex X'taħseb.

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Huwa ħafna, ħafna agħar.

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Jekk inti ma jagħtux me-kombinazzjoni li l-ilqugħ arja, Dr Schlotkin se

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tagħti t-tifla tiegħek lura imnieħer qadim tagħha.

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-Nru!

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Fejn ma ikollok dan?

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-Kull dritt.

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I ser jgħidlek.

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I ser jgħidlek.

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-Nru, daddy, l-ebda.

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Inti ma għandu.

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You're-dritt, għeżież tiegħi.

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I ser titlef imnieħer ġdida tiegħek.

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Imma jien mhux ser jgħidulhom il-kombinazzjoni x'ikun.

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-Tajjeb ħafna.

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Dr Schlotkin, do agħar tiegħek.

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-Tiegħi divertiment.

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-Nru!

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Stenna, stenna.

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I ser jgħidlek.

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I ser jgħidlek.

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-I kien jaf ikun xogħol.

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Kull dritt, tagħtiha lili.

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-Il-kombinazzjoni hija waħda.

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-One.

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-One.

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-Żewġ.

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-Żewġ.

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-Żewġ.

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-Tliet

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-Tliet.

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-Tliet.

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-Erba.

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-Erba.

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-Erba.

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-Ħames

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-Ħames.

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-Ħames.

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-Allura-kombinazzjoni hija wieħed, tnejn, tlieta, erba ', ħames.

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Dik hija l-kombinazzjoni stupidest I qatt semgħu fil-ħajja tiegħi.

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Dik hija l-tip ta 'ħaġa idjota jkollha fuq bagalji tiegħu.

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-Grazzi, Altezza tiegħek.

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-What did you do?

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-I daru off-ħajt.

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-Le, inti ma.

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Inti mitfija l-film kollu.

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-I irid ikun ippressat-buttuna ħażina.

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Well, erġa 'poġġih fuq.

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Poġġi l-film lura fuq.

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-Iva, sir.

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Iva, sir.

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-Ejja ħa mmorru, Erna.

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Come, Gretchen.

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Tal-kors li inti taf I taf xorta jkollhom inti kont għal dan.

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Well, ma taħdem?

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Fejn hi l-bieb?

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-It maħduma, sir.

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Għandna l-kombinazzjoni.

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-Kbir.

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Issa nistgħu jieħdu kull aħħar nifs ta 'arja friska minn pjaneta Druidia.

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X'hemm-kombinazzjoni?

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-Wieħed, tnejn, tlieta, erba ', ħames.

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-Wieħed, tnejn, tlieta, erba ', ħames?

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-Iva.

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-Li aqwa.

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Stajt ltqajna l-kombinazzjoni istess fuq bagalji tiegħi.

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Ipprepara Spaceball 1 għall-tluq immedjat.

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-Iva, sir.

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U l-bidla l-kombinazzjoni fuq bagalji tiegħi.

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-Ow!

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[END video daqq]

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>> DAVID J. Malan: An movie aqwa għandek issa kulħadd jara.

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Allura l-kuntest hawnhekk hija li ma 'data mhux sikuri ġejja l-opportunità li

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kriptaġġ u biex ġirja dan.

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U hekk dan, per eżempju, huwa eżempju ta 'messaġġ encrypted.

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Dan fil-fatt jgħid xi ħaġa bl-Ingliż.

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Iżda huwa ċar mhumiex totalment ovvji.

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U aħna ser jiġu ċirku sħiħ llum biex tease apparti dak li din sigriet

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messaġġ hawnhekk huwa.

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Imma fid-dinja reali ta 'kompjuters, l-affarijiet ma anki look like dawn jistgħu

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jkun frażijiet Ingliż.

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Per eżempju, dan huwa dak li inti tista 'ssib fuq Linux jew Mac standard jew

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Kompjuter Unix fil-fajl li kienet darba fuq żmien imsejjaħ il-fajl password.

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Illum, huwa kien imċaqlaq għall-postijiet l-oħra.

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Imma jekk inti tfittex fil-post it-tajjeb fuq sistema, tkun taf tara mhux biss tiegħek

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username jew dik ta 'persuni oħra fuq is-sistema, iżda inti ser tara

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Verżjoni encrypted password ta 'tagħhom.

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Tabilħaqq, il-kripta kelma hemmhekk jissuġġerixxi li l-għalf li ġej huwa encrypted.

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U din is-serje ta 'ittri apparentement każwali u karattri u numri u

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ibqa 'sejjer hekk jistgħu jiġu decrypted biss bil ġeneralment jaf xi sigriet -

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kelma sigrieta, numru sigriet.

194
00:07:58,600 --> 00:08:02,760
U għalhekk fil-fatt, l-arti tal-kriptografija finalment jeħodna għall-fiduċja ta 'xi

195
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sort u jafu xi ħaġa li xi ħadd ieħor ma.

196
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Aħna ser tesplora dan fid-dettall daqsxejn aktar llum u fil-pset li ġejjin.

197
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>> U issa l-kelma fuq għadda / jonqsu.

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Allura speċjalment, kif xi wħud minnkom dived fis pset 1, l-apparat, u

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dinja ferm ġdida għalik innifsek, realizzati li frustrazzjonijiet u

200
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diffikultajiet konfużjoni u biss tekniċi huma mistennija.

201
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Speċjalment ma 'l-pset 1, fejn hemm biss tant ġodda, biss jkollna

202
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familjari ma 'ls u cd u kollha dawn il-kmandijiet arcane f'ambjent ġdid.

203
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U li separata mill-materja attwali u l-ipprogrammar innifsu.

204
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Allura realizzata, wisq, li hemm ċertament ħinijiet tal-uffiċċju li jeżistu bħala

205
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l-istruttura ta 'appoġġ.

206
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Taqsimiet jibda dan il-Ħadd li ġej.

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Iżda aktar importanti, jekk int tħossok ftit li dan mhuwiex il-

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dinja għalik, tirrealizza li huwa verament ma biss jieħu ż-żmien.

209
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U kieku ma kienx għal din l-opportunità snin ilu għalija li tittieħed klassi

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suċċess / falliment, onestament, jien qatt ma saħansitra sett marda fil-klassi.

211
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U inti tista 'tbiddel dan sa, ngħidu aħna, it-Tnejn 5 tal-kors.

212
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Mela jekk int fuq it-tarf issa, jirrealizzaw li aktar milli ras fis xi oħra

213
00:08:57,110 --> 00:09:01,000
ilmijiet kollox, do ċertament jikkunsidraw ftit tibdil biex suċċess / falliment.

214
00:09:01,000 --> 00:09:03,750
Għal darb'oħra, hemm mhux verament din il-kultura hawn fil-Harvard li jieħdu l-affarijiet

215
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suċċess / falliment peress li kulħadd verament jixtieq li jilħqu jew taqbeż il.

216
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Iżda franchement, dan huwa wunderbare mod ta 'tipprova xi ħaġa li jista' ma

217
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ikun familjari għalik.

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U tkun taf jispiċċaw jagħmlu f'ħafna każijiet pjuttost multa, forsi

219
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ħafna biex sorpriża tiegħek.

220
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U f'termini iktar konkreti, dak li naħseb suċċess / falliment ġeneralment ma,

221
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speċjalment peress li inti jista 'jkollok esperjenza bil pset 0, jekk inti stajt tpoġġi

222
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fl-10 siegħa, 15 siegħa, 25 siegħa fi ftit pset - u inti qed biss banging

223
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ras tiegħek kontra l-ħajt,

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u huwa jkollna super tard bil-lejl,

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imma inti ħadt il-pset simili 90% mill-mod,

226
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inti taf li inti biss ma tistax figura ħaġa waħda -

227
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suċċess / falliment verament jieħu l-tarf off ta 'klassi bħal din, fejn inti tista sort

228
00:09:36,830 --> 00:09:39,150
ta heureusement jgħidu okay, I know mhuwiex perfett.

229
00:09:39,150 --> 00:09:40,470
Imma I maħduma ħmar tiegħi off fuq dan.

230
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Jien pjuttost kuntenti bil fejn spiċċaw.

231
00:09:42,410 --> 00:09:44,780
U li se jilħqu l-aspettattivi għal suċċess / falliment.

232
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Allura iżommu dan f'moħħhom.

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>> Kull dritt.

234
00:09:47,140 --> 00:09:50,980
Allura dawk fostkom li għadhom tħabtu biex jużaw l-Università ta 'Harvard Wi-Fi taf

235
00:09:50,980 --> 00:09:54,780
li hemm SSID CS50, konnessjoni Wi-Fi f'wiċċ l-ilma madwar li inti

236
00:09:54,780 --> 00:09:56,520
jista 'jkollhom Xorti aħjar għall.

237
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Huwa ironiku ftit li l-password għal dan - jekk inti tixtieq li jippruvaw

238
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konnessjoni għal dan għal veloċitajiet aħjar u jgħidilna jekk l-ebda aħjar -

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huwa wieħed, tnejn, tlieta, erba ', ħames, it-triq kollha sa tmien għaliex 8 huwa

240
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aktar sikuri minn ħamsa.

241
00:10:10,270 --> 00:10:15,520
Mela jekk għandek bżonn l-password Wi-Fi, jgħaqqdu wirelessly CS50 hawn.

242
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Wieħed, tnejn, tlieta, erba ', ħames, sitt, seba', tmien.

243
00:10:16,950 --> 00:10:20,440
U post fuq CS50 Iddiskuti jekk inti għad għandek kwistjonijiet konnettività intermittenti,

244
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u aħna ser let-setgħat li jiġu jafu għal dan l-ispazju.

245
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>> Kull dritt.

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00:10:25,180 --> 00:10:30,350
Allura teaser malajr, speċjalment għal dawk minnkom li huma subien fann jew bniet

247
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ta 'kulħadd Apple affarijiet.

248
00:10:31,900 --> 00:10:37,566
What I dug up minn ftit snin lura kien dan il-fajl hawn, ilock.c, just biex

249
00:10:37,566 --> 00:10:40,930
tip ta 'juri b'mod aktar konkret u aktar kumplessi xi wħud mill-aktar bażika C

250
00:10:40,930 --> 00:10:42,350
Programmi aħna kont qed miktub.

251
00:10:42,350 --> 00:10:44,360
So I fetaħ dan il-fajl, ilock.c.

252
00:10:44,360 --> 00:10:46,830
Huwa disponibbli fuq il-paġna lekċers għal-lum.

253
00:10:46,830 --> 00:10:49,470
Fuq in-naħa tax-xellug, inti tara lista twila ta 'funzjonijiet.

254
00:10:49,470 --> 00:10:51,860
Allura l-kollegi li kiteb dan kiteb ħafna ta 'funzjonijiet,

255
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aktar milli sempliċiment prinċipali.

256
00:10:53,290 --> 00:10:55,490
Huwa użat mazz sħiħ ta 'libreriji hawn.

257
00:10:55,490 --> 00:11:00,450
U jekk nibdew scrolling permezz ta ', dak li din fil-fatt hija l-ħafna

258
00:11:00,450 --> 00:11:04,670
1, nemmen, xquq għall-iPhone oriġinali.

259
00:11:04,670 --> 00:11:08,000
Meta inti riedu jailbreak l-iPhone oriġinali, li jfisser untether

260
00:11:08,000 --> 00:11:11,800
minn AT & T u fil-fatt tinstalla software speċjali fuqha u jagħmlu affarijiet

261
00:11:11,800 --> 00:11:13,510
li Apple ma riedx nies biex jagħmlu -

262
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ukoll, xi ħadd ħa l-ħin biex insemmu eżattament kif jistgħu jisfruttaw

263
00:11:17,020 --> 00:11:20,880
softwer difetti, żbalji, bugs, fis-software Apple.

264
00:11:20,880 --> 00:11:22,650
U għalhekk twieled ilock.c.

265
00:11:22,650 --> 00:11:26,670
Li jekk inti miġbura fuq il-kompjuter u installati hija fuq iPhone li

266
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kienu konnessi mal-kompjuter tiegħek permezz, ngħidu aħna, USB cable, dan jagħtik

267
00:11:29,810 --> 00:11:33,360
privileġġi amministrattivi jew għerq fuq iPhone tiegħek u tavżak tagħmel pretty ħafna

268
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tkun xi tkun trid.

269
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>> U hekk hemm kien dan il-qtates affaxxinanti u kaċċa maws bejn Apple u

270
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il-bqija tad-dinja, b'mod partikolari peress li, bħal ħafna kumpaniji, jippruvaw biex jissakkar

271
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Jittieħed tagħhom stabbiliti sabiex inti tista 'biss tagħmel magħha dak li bi ħsiebhom.

272
00:11:43,220 --> 00:11:46,620
Iżda grazzi għall-persuni bħal dan u l-fehim tagħhom ta 'livell baxx

273
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dettalji u, f'dan il-każ, programmazzjoni C u ħafna ta 'l-constructs familjari

274
00:11:50,580 --> 00:11:54,630
li konna bdew jilagħbu ma ', inti tista' verament jwieżen l-

275
00:11:54,630 --> 00:11:59,050
ħardwer b'mod tara xieraq u mhux neċessarjament xi entità korporattiva.

276
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Għalhekk per eżempju, għandi l-ebda idea dak li dan kollu qed tagħmel.

277
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Iżda GetVersion ħsejjes pjuttost sempliċi.

278
00:12:03,220 --> 00:12:05,480
U jidher qisu dan huwa funzjoni li din il-persuna kiteb.

279
00:12:05,480 --> 00:12:09,240
Jieħdu xi tip ta 'numru sħiħ bħala argument, ma ritorn xejn, imma

280
00:12:09,240 --> 00:12:13,080
jidher li loop bi għar loop hawn u jekk il-kundizzjoni, jekk il-kundizzjoni,

281
00:12:13,080 --> 00:12:15,620
break, u b'xi mod tirrigwarda n-numri verżjoni.

282
00:12:15,620 --> 00:12:16,700
Jekk aħna iscroll -

283
00:12:16,700 --> 00:12:19,570
anke jekk ħafna ta 'dawn keywords ser ikunu ġodda, u hemm

284
00:12:19,570 --> 00:12:22,590
lott kollu ta 'funzjonijiet fl here we ve qatt u ma tista qatt tara fuq

285
00:12:22,590 --> 00:12:23,830
il-kors tas-semestru -

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00:12:23,830 --> 00:12:27,150
fl-aħħar tal-ġurnata, isegwi l-istess regoli u l-loġika li aħna kont qed

287
00:12:27,150 --> 00:12:28,760
playing mal s'issa.

288
00:12:28,760 --> 00:12:34,220
Allura dan huwa wisq antik biex jitwaqqaf 3s iPhone tiegħek jew 4s jew ftit 5s, dawn il-ġranet,

289
00:12:34,220 --> 00:12:37,320
imma jafu li dan kollu ħafna derivat minn din id-dinja li aħna ħadthom

290
00:12:37,320 --> 00:12:38,430
dived fis.

291
00:12:38,430 --> 00:12:41,900
>> Mela ejja tagħti ħarsa lejn eżempju ftit aktar sempliċi.

292
00:12:41,900 --> 00:12:46,100
Dan wieħed, biss li tikseb msaħħna ma 'xi sintassi u wkoll xi data oħra

293
00:12:46,100 --> 00:12:49,240
tip li konna tkellimna dwar iżda ma verament jidhru C. Allura dan huwa

294
00:12:49,240 --> 00:12:51,680
fajl imsejjaħ positive1.c.

295
00:12:51,680 --> 00:12:55,120
U kull l-kummenti fil-quċċata, dan biss jitlob li utent jipprovdu

296
00:12:55,120 --> 00:12:55,960
pożittiv numru.

297
00:12:55,960 --> 00:12:59,530
Allura huwa eżempju ta 'loop do-waqt, li huwa sbieħ għall-utent interattiv

298
00:12:59,530 --> 00:13:01,980
programmi fejn għandek bżonn li tgħid l-utent li jagħmel xi ħaġa.

299
00:13:01,980 --> 00:13:05,190
U jekk dawn ma jikkoperaw, inti Yell fil minnhom jew tirrifjuta l-kontribut tagħhom.

300
00:13:05,190 --> 00:13:11,610
Kawża fil-punt, jiena ser tagħmel linji 19 permezz 24 sakemm l-utent ikollu

301
00:13:11,610 --> 00:13:14,310
ma tani numru pożittiv.

302
00:13:14,310 --> 00:13:20,400
Issa dan id-dettall hawn fuq il-linja 18, għaliex ma niddikjara n ogħla minn dan kollu

303
00:13:20,400 --> 00:13:24,490
tibni looping għall-kuntrarju dritt li jmiss għal-linja 22 fejn I

304
00:13:24,490 --> 00:13:26,880
attwalment kura biex tikseb n?

305
00:13:26,880 --> 00:13:27,330
Yeah?

306
00:13:27,330 --> 00:13:27,780
[Inaudible]

307
00:13:27,780 --> 00:13:29,040
>> DAVID J. Malan: Yeah, hekk din il-kwistjoni tal-ambitu.

308
00:13:29,040 --> 00:13:30,850
U fit-terminu layman, dak ma iskop jirreferu għall?

309
00:13:34,690 --> 00:13:36,610
Yeah?

310
00:13:36,610 --> 00:13:37,860
[Inaudible]

311
00:13:40,040 --> 00:13:41,105
DAVID J. Malan: Tista titkellem ftit louder?

312
00:13:41,105 --> 00:13:43,450
SPEAKER 1: Fejn inti tista 'aċċess varjabbli partikolari.

313
00:13:43,450 --> 00:13:45,170
DAVID J. Malan: Perfect.

314
00:13:45,170 --> 00:13:47,360
Fejn inti tista 'aċċess varjabbli partikolari.

315
00:13:47,360 --> 00:13:50,400
U ġeneralment, ir-regola ta 'thumb s'issa kienet li l-ambitu ta' xi

316
00:13:50,400 --> 00:13:55,860
varjabbli huwa definit mill-braces kaboċċi aktar riċenti li inti stajt tidher.

317
00:13:55,860 --> 00:14:02,010
U hekk f'dan il-każ, jekk I għamel l-iżball li tiddikjara n fuq il-linja 22,

318
00:14:02,010 --> 00:14:03,010
dik il-linja tkun taħdem.

319
00:14:03,010 --> 00:14:10,990
Nixtieq nikseb int, u jien poġġih fil dak n-varjabbli fil-linja 22.

320
00:14:10,990 --> 00:14:16,900
Iżda li linja tal-kodiċi issa se jkollhom l-ebda idea dak li nkun qiegħed jitkellem dwar?

321
00:14:16,900 --> 00:14:22,650
Allura 25, u jirriżulta 24, kif ukoll, minħabba f'dan il-każ, dan jaqa 'barra

322
00:14:22,650 --> 00:14:23,610
taċ-ċingi kaboċċi.

323
00:14:23,610 --> 00:14:27,280
Hekk biss ftit ta 'inkonvenjent, iżda faċilment solvuti billi sempliċement iddikjarat li

324
00:14:27,280 --> 00:14:30,140
barra varjabbli tal-funzjoni stess.

325
00:14:30,140 --> 00:14:32,600
>> Issa aħna ser tara aktar tard illum, inti tista 'tmur pass ulterjuri.

326
00:14:32,600 --> 00:14:34,860
U inti tista 'anki jiksbu ftit għażżien -

327
00:14:34,860 --> 00:14:37,320
u dan m'għandux jiġi rakkomandat, b'mod ġenerali -

328
00:14:37,320 --> 00:14:42,260
imma int tista 'wkoll tikseb għażżien u mqiegħda varjabbli globalment, biex ngħidu hekk, ma

329
00:14:42,260 --> 00:14:46,670
ġewwa ta 'funzjoni, mhux ġewwa ta' linja, iżda fil-fajl innifsu, barra

330
00:14:46,670 --> 00:14:49,600
ta 'kollha tal-funzjonijiet li inti stajt bil-miktub, kif għamilt hawn fuq il-linja 15.

331
00:14:49,600 --> 00:14:51,160
Iżda din hija ġeneralment frowned fuq.

332
00:14:51,160 --> 00:14:55,680
Iżda realizzata din hija soluzzjoni kultant għal problemi oħra, kif aħna ser

333
00:14:55,680 --> 00:14:56,620
eventwalment tara.

334
00:14:56,620 --> 00:14:58,130
Allura għal issa, aħna ser jitilqu minnu bħal dan.

335
00:14:58,130 --> 00:15:01,030
Imma ejja ara jekk nistgħu jikteb dan biss biex tibda jesprimu nfusna a

336
00:15:01,030 --> 00:15:01,990
ftit differenti.

337
00:15:01,990 --> 00:15:05,330
>> Allura dan il-programm, biss biex ikunu ċari, huwa positive1.

338
00:15:05,330 --> 00:15:11,810
Let me imorru quddiem u hawn fil-tieqa terminal tiegħi jagħmlu positive1, Ikteb.

339
00:15:11,810 --> 00:15:12,740
Jikkompila, okay.

340
00:15:12,740 --> 00:15:14,910
Jien ser jimxu positive1, hit Ikteb.

341
00:15:14,910 --> 00:15:16,820
I domanda li inti tagħti me numru sħiħ pożittiv.

342
00:15:16,820 --> 00:15:18,260
I ser ngħid -1.

343
00:15:18,260 --> 00:15:18,910
Li ma ħadmux.

344
00:15:18,910 --> 00:15:22,150
0, 99, li jidher li qed jaħdem.

345
00:15:22,150 --> 00:15:23,570
Forsi mhux l-aktar test rigoruża.

346
00:15:23,570 --> 00:15:26,480
Imma l-anqas huwa kontroll sanità sbieħ li aħna qed fuq il-binarju dritt.

347
00:15:26,480 --> 00:15:29,240
Allura issa let me imorru quddiem u tiftaħ verżjoni 2 ta 'dan.

348
00:15:29,240 --> 00:15:32,500
U dak li huwa differenti diġà?

349
00:15:32,500 --> 00:15:35,140
Hija timplimenta l-istess ħaġa.

350
00:15:35,140 --> 00:15:40,660
Imma x'hemm qbiż b'mod ċar differenti dan iż-żmien?

351
00:15:40,660 --> 00:15:42,560
Yeah, għalhekk dan bool fl-aħdar.

352
00:15:42,560 --> 00:15:45,980
Gedit enfasizzat fl-aħdar dan il-keyword magħrufa bħala bool,

353
00:15:45,980 --> 00:15:47,000
li huwa tip ta 'data.

354
00:15:47,000 --> 00:15:51,080
Ma jiġu mibnija għall-verżjonijiet kollha ta 'C. Ikollok bżonn li tinkludi

355
00:15:51,080 --> 00:15:52,010
speċifiku librerija.

356
00:15:52,010 --> 00:15:54,770
Fil-każ tagħna, I inklużi l-librerija CS50 sabiex inkunu

357
00:15:54,770 --> 00:15:56,460
jkollhom aċċess għall-bool.

358
00:15:56,460 --> 00:15:59,810
Iżda fil-linja 18, aħna jidhru li jkollhom valur Boolean hawn imsejjaħ thankful.

359
00:15:59,810 --> 00:16:01,040
So I setgħet sejjaħ din xejn.

360
00:16:01,040 --> 00:16:04,500
Imma I sejħitilha thankful biss li tip ta 'twassal xi tifsira semantika.

361
00:16:04,500 --> 00:16:07,930
Allura inizjalment fuq il-linja 18, jien apparentement ma thankful minħabba li l-

362
00:16:07,930 --> 00:16:12,150
Valur Boolean thankful huwa initialized li foloz fil-linja 18.

363
00:16:12,150 --> 00:16:16,890
U allura jidher dak I ghamilt hawn fil-linji 21 permezz 23 huwa Stajt biss

364
00:16:16,890 --> 00:16:18,610
tip ta 'tinkiteb mill-ġdid loġika tiegħi.

365
00:16:18,610 --> 00:16:21,020
Allura l-ebda funzjonalment differenti.

366
00:16:21,020 --> 00:16:26,940
Iżda fil-linja 22 issa, I jivverifika jekk l-int-utent ikun ipprovda huwa akbar minn

367
00:16:26,940 --> 00:16:31,120
0, imbagħad I sempliċiment ibiddlu l-valur tal-thankful għall veru.

368
00:16:31,120 --> 00:16:32,290
U għaliex nista 'nagħmlu?

369
00:16:32,290 --> 00:16:35,600
Minħabba fil-linja 25, apparentement, jien ser jiċċekkja kundizzjoni.

370
00:16:35,600 --> 00:16:39,380
Agħmel dan loop filwaqt huwa thankful falza.

371
00:16:39,380 --> 00:16:43,610
>> So nipproponi dan bħala alternattiva għall-verżjoni 1 għaliex dan huwa mill-inqas

372
00:16:43,610 --> 00:16:45,130
ftit aktar intuwittivi, forsi.

373
00:16:45,130 --> 00:16:46,900
Huwa ftit aktar milli jtir bl-Ingliż.

374
00:16:46,900 --> 00:16:51,710
Allura tagħmel dan li ġej waqt li inti mhux thankful jew waqt li tkun thankful falza.

375
00:16:51,710 --> 00:16:55,890
U din id-darba, ukoll, I apparentement ma 'kura li tiftakar dak li l-utent ittajpjat

376
00:16:55,890 --> 00:16:57,730
fil minħabba avviż hemm l-ebda n varjabbli.

377
00:16:57,730 --> 00:16:58,650
Allura fil-fatt, I -

378
00:16:58,650 --> 00:17:00,080
gidba ftit abjad hemmhekk.

379
00:17:00,080 --> 00:17:02,770
Funzjonalment, il-programm huwa daqsxejn differenti ladarba irridu jiksbu l-qiegħ ta '

380
00:17:02,770 --> 00:17:04,819
għaliex jien ma ftakar dak n hija.

381
00:17:04,819 --> 00:17:09,579
Imma jien ridt li juru hawnhekk ukoll li anke jekk aħna stajt tidher GetInt u

382
00:17:09,579 --> 00:17:13,920
GetString qed jintużaw fuq in-naħa tal-lemin ta 'sinjal ugwali s'issa sabiex

383
00:17:13,920 --> 00:17:17,160
aħna niftakru l-valur, teknikament, li mhux strettament neċessarju.

384
00:17:17,160 --> 00:17:20,950
Jekk għal kwalunkwe raġuni inti biss ma 'kura biex isalva l-valur, inti biss trid

385
00:17:20,950 --> 00:17:25,710
biex jivverifika l-valur, avviż li nistgħu sempliċement jiktbu dan bħala GetInt miftuħ

386
00:17:25,710 --> 00:17:27,000
paren, paren qrib.

387
00:17:27,000 --> 00:17:30,460
Din il-funzjoni se terġa 'lura għal valur, kif aħna kont qed tgħid.

388
00:17:30,460 --> 00:17:32,010
Huwa ser jagħtuk lura int.

389
00:17:32,010 --> 00:17:36,450
U għalhekk jekk inti mentalment taħseb li dan jiġri, meta I tip 99, GetInt

390
00:17:36,450 --> 00:17:38,160
jirritorna l-għadd 99.

391
00:17:38,160 --> 00:17:41,330
U għalhekk kunċettwali, huwa daqs li kieku kodiċi tiegħi kienu attwalment dan.

392
00:17:41,330 --> 00:17:45,880
Mela jekk 99 huwa tabilħaqq ikbar minn 0, imbagħad isir thankful veru.

393
00:17:45,880 --> 00:17:50,420
Imbagħad linja 25 jirrealizza ooh, aħna qed isir għaliex jien issa thankful.

394
00:17:50,420 --> 00:17:54,590
U fil-linja 26, aħna sempliċiment ngħidu, grazzi għall-eqreb numru sħiħ pożittiv, tkun xi

395
00:17:54,590 --> 00:17:55,710
li jkun ġara.

396
00:17:55,710 --> 00:17:58,900
>> Issa ejja nagħmlu zokkor sintattika żgħir hawn, biex ngħidu hekk.

397
00:17:58,900 --> 00:18:02,990
Ejja naraw jekk nistgħu tnaddaf din il-linja 25 ma 'dan varjanza tielet u finali

398
00:18:02,990 --> 00:18:04,640
fil positive3.

399
00:18:04,640 --> 00:18:08,250
Allura avviż-differenza biss issa huwa dak linja tal-kodiċi?

400
00:18:11,930 --> 00:18:13,260
Yeah, hekk 25.

401
00:18:13,260 --> 00:18:15,520
U aħna stajt ma verament jidhru dan trick għadha biss.

402
00:18:15,520 --> 00:18:19,510
Iżda aħna ma tara l-punt exclamation-Tnejn, li tindika liema?

403
00:18:19,510 --> 00:18:20,970
Allura le, jew negazzjoni.

404
00:18:20,970 --> 00:18:23,460
Allura jieħdu valur Boolean u flip-valur tagħha.

405
00:18:23,460 --> 00:18:24,390
Veru isir falza.

406
00:18:24,390 --> 00:18:25,500
Foloz isir veru.

407
00:18:25,500 --> 00:18:28,910
Allura dan, nixtieq nipproponi, huwa saħansitra xi ftit aktar intuwittivi ta 'mod ta'

408
00:18:28,910 --> 00:18:32,200
miktub l-kodiċi minħabba I xorta initialize thankful għall falza.

409
00:18:32,200 --> 00:18:33,530
I għadhom jagħmlu dan li ġej.

410
00:18:33,530 --> 00:18:35,700
I sett thankful għall veru meta jasal iż-żmien.

411
00:18:35,700 --> 00:18:40,690
Imma issa inti tista 'verament ftit tittraduċi din il-kodiċi verbalment xellug għal-lemin,

412
00:18:40,690 --> 00:18:42,550
filwaqt li ma thankful.

413
00:18:42,550 --> 00:18:46,170
Minħabba bang, jew il-punt exclamation, tindika l-kunċett ta 'le, sabiex filwaqt li

414
00:18:46,170 --> 00:18:47,010
mhux thankful.

415
00:18:47,010 --> 00:18:49,740
>> Għalhekk għal darb'oħra, aħna ma introduċiet l-ebda kunċetti ġodda per se.

416
00:18:49,740 --> 00:18:53,230
Imxejna tkellem dwar Booleans lura meta aħna lagħbu Scratch.

417
00:18:53,230 --> 00:18:55,690
Imma tirrealizza issa nistgħu biss tibda tikteb kodiċi tagħna fl-

418
00:18:55,690 --> 00:18:56,550
modi differenti.

419
00:18:56,550 --> 00:19:00,010
Allura speċjalment fil pset1, jekk int-tip ta 'tissara biex insemmu l-mod li

420
00:19:00,010 --> 00:19:03,400
jikteb xi programm, odds huma int fil Xorti għaliex hemm għaddej li tkun kwalunkwe

421
00:19:03,400 --> 00:19:05,780
numru ta 'soluzzjonijiet li inti jista' jiġri fuq.

422
00:19:05,780 --> 00:19:09,850
Per eżempju, dan huwa biss tlieta għall anki l-aktar sempliċi ta 'programmi.

423
00:19:09,850 --> 00:19:10,180
Kull dritt.

424
00:19:10,180 --> 00:19:13,860
U issa lura nhar it-Tnejn, aħna xellug fuq din in-nota ma 'valuri ta' ritorn.

425
00:19:13,860 --> 00:19:18,280
Allura għall-ewwel darba, aħna kiteb programm li ma biss ikollhom prinċipali,

426
00:19:18,280 --> 00:19:22,240
għandu wkoll il-funzjoni tad-dwana tagħha stess li I kiteb hawn.

427
00:19:22,240 --> 00:19:26,640
Allura fil-linja 31 permezz 34, stajt implimentati funzjoni kubu.

428
00:19:26,640 --> 00:19:27,800
Mhuwiex kumplessi.

429
00:19:27,800 --> 00:19:29,830
Huwa biss il-darba xi drabi a, f'dan il-każ.

430
00:19:29,830 --> 00:19:34,920
Imma x'hemm importanti dwar dan hija li jien teħid input fil-forma ta 'u

431
00:19:34,920 --> 00:19:38,910
Jien lura output fil-forma ta 'drabi darbiet a.

432
00:19:38,910 --> 00:19:43,940
>> Allura issa għandi l-abbiltà, simili ħafna I użati biex ma printf biss, għal sejħa

433
00:19:43,940 --> 00:19:47,120
din il-funzjoni billi ċċempel l-funzjoni kubu.

434
00:19:47,120 --> 00:19:49,470
U l-funzjoni kubu jieħu xi input.

435
00:19:49,470 --> 00:19:52,030
U l-funzjoni kubu lura xi output.

436
00:19:52,030 --> 00:19:56,660
U hekk b'kuntrast, printf biss għamlet xi ħaġa.

437
00:19:56,660 --> 00:19:59,490
Hija ma reġgħux lura xejn li aħna jieħdu ħsiebhom dwar - anki jekk, bħala

438
00:19:59,490 --> 00:20:00,820
twarrib, dan ma ritorn ta 'valur.

439
00:20:00,820 --> 00:20:02,650
Inti biss ġeneralment jinjoraha.

440
00:20:02,650 --> 00:20:04,000
Printf biss għamlet xi ħaġa.

441
00:20:04,000 --> 00:20:06,220
Hija kellha effett sekondarju ta 'l-istampar l-iskrin.

442
00:20:06,220 --> 00:20:09,480
B'kuntrast hawn, aħna għandna l-funzjoni kubu, li

443
00:20:09,480 --> 00:20:11,400
attwalment prospetti xi ħaġa.

444
00:20:11,400 --> 00:20:12,960
>> Allura dan huwa ġeneralment -

445
00:20:12,960 --> 00:20:15,260
għal dawk familjari ma 'dan, din hija idea pjuttost sempliċi.

446
00:20:15,260 --> 00:20:18,460
Iżda għal dawk inqas familjari ma din l-idea li tgħaddi fil-inputs u jkollna

447
00:20:18,460 --> 00:20:21,700
outputs lura, ejja ipprova biss xi ħaġa sempliċi super.

448
00:20:21,700 --> 00:20:25,180
Huwa xi ħadd komdu ġejjin fuq il-palk fil-qosor?

449
00:20:25,180 --> 00:20:27,460
Int għandek tkun komda ma 'kamera fuqek, kif ukoll.

450
00:20:27,460 --> 00:20:27,640
Yeah.

451
00:20:27,640 --> 00:20:28,610
Okay, dak l-isem tiegħek?

452
00:20:28,610 --> 00:20:29,020
KEN: Ken.

453
00:20:29,020 --> 00:20:29,420
DAVID J. Malan: Ken.

454
00:20:29,420 --> 00:20:29,810
Kull dritt, Ken.

455
00:20:29,810 --> 00:20:31,060
Come fuq up.

456
00:20:31,060 --> 00:20:34,660
Allura Ken se tkun funzjoni ta 'tip hawn.

457
00:20:34,660 --> 00:20:35,760
U ejja imorru quddiem u jagħmlu dan.

458
00:20:35,760 --> 00:20:38,790
Ejja jiksbu fancy ftit.

459
00:20:38,790 --> 00:20:39,770
Nizza biex jissodisfaw inti.

460
00:20:39,770 --> 00:20:41,010
Merħba għall-istadju taċ-ċentru.

461
00:20:41,010 --> 00:20:41,980
Kull dritt.

462
00:20:41,980 --> 00:20:45,590
Ejja hit din il-buttuna hawn.

463
00:20:45,590 --> 00:20:46,420
Kull dritt.

464
00:20:46,420 --> 00:20:49,490
Allura hawnhekk għandek chalkboard moderna.

465
00:20:49,490 --> 00:20:53,050
U dak I am hija l-funzjoni prinċipali, per eżempju.

466
00:20:53,050 --> 00:20:55,990
U jien ma jkollhom iPad fl-idejn tiegħi.

467
00:20:55,990 --> 00:20:59,000
I ma verament tiftakar kif - ukoll, fil-fatt, ma nistax ngħid li.

468
00:20:59,000 --> 00:21:02,200
I ma verament ikollhom kalligrafija tajba.

469
00:21:02,200 --> 00:21:05,260
U hekk għalhekk, nixtieq li jistampaw xi ħaġa fuq l-iskrin għalija.

470
00:21:05,260 --> 00:21:07,470
>> So I am huwa l-programm prinċipali.

471
00:21:07,470 --> 00:21:15,060
U jiena se jkollhom inti ngħid dan bil-kitba fil-bidunett tat-tiġieġ tiegħi u

472
00:21:15,060 --> 00:21:16,600
imbagħad jgħaddi inti input.

473
00:21:16,600 --> 00:21:20,000
Allura kif iblah jekk dan l-eżerċizzju huwa, il-kunċett tal-funzjonijiet u sejħa

474
00:21:20,000 --> 00:21:22,260
funzjoni u r-ritorn funzjoni verament jeħodna għal dan.

475
00:21:22,260 --> 00:21:23,120
I am prinċipali.

476
00:21:23,120 --> 00:21:26,270
I għadek miktub printf ("xi ħaġa") fuq l-iskrin.

477
00:21:26,270 --> 00:21:27,470
Niġri dan il-programm.

478
00:21:27,470 --> 00:21:30,900
U hekk kif printf gets imsejħa, hija tieħu 1 argument - jew parametru wieħed,

479
00:21:30,900 --> 00:21:31,660
kultant -

480
00:21:31,660 --> 00:21:32,780
bejn kwotazzjonijiet doppja.

481
00:21:32,780 --> 00:21:33,960
Hawnhekk huwa dan l-argument.

482
00:21:33,960 --> 00:21:35,740
Jien tgħaddi lill Ken.

483
00:21:35,740 --> 00:21:39,390
Issa huwa kaxxa sewda bil-miktub xi numru ta 'snin ilu li apparentement

484
00:21:39,390 --> 00:21:41,070
biss jaf kif jistampaw affarijiet fuq l-iskrin.

485
00:21:41,070 --> 00:21:42,320
>> Allura, tesegwixxi.

486
00:21:48,842 --> 00:21:49,900
Li mhux ħażin.

487
00:21:49,900 --> 00:21:50,890
Allura, tajba ħafna.

488
00:21:50,890 --> 00:21:52,900
Allura issa Ken isir esekuzzjoni.

489
00:21:52,900 --> 00:21:55,810
Ma hu bżonn idejn lili xejn lura?

490
00:21:55,810 --> 00:21:57,240
Allura mhux li Rajna s'issa.

491
00:21:57,240 --> 00:21:59,230
Għal darb'oħra, printf ma attwalment ritorn ta 'numru.

492
00:21:59,230 --> 00:22:01,640
Iżda aħna qed tmur biex jinjoraw li għal issa għaliex aħna qatt ma stajt użati dan.

493
00:22:01,640 --> 00:22:03,400
Allura dak li għal Ken.

494
00:22:03,400 --> 00:22:06,650
U hekk issa ġejja prinċipali lura biex tesegwixxi -

495
00:22:06,650 --> 00:22:09,630
prinċipali jieħu f'idejh kontroll tal-programm mill-ġdid minħabba li l-linja tal-kodiċi,

496
00:22:09,630 --> 00:22:11,010
printf, isir esekuzzjoni.

497
00:22:11,010 --> 00:22:13,890
U aħna tmur dwar mod tagħna teżegwixxi kwalunkwe linji oħra hemm.

498
00:22:13,890 --> 00:22:14,130
>> Kull dritt.

499
00:22:14,130 --> 00:22:17,080
Allura issa ejja ipprova eżempju kemmxejn differenti.

500
00:22:17,080 --> 00:22:22,430
U din id-darba hawn, ejja ewwel ċar l-iskrin hawn.

501
00:22:22,430 --> 00:22:24,670
U dan iż-żmien, aħna ser nagħmlu l-funzjoni cubing.

502
00:22:24,670 --> 00:22:27,350
Iżda dan iż-żmien, nistenna valur ta 'produzzjoni.

503
00:22:27,350 --> 00:22:28,630
Mela ejja imorru quddiem u jagħmlu dan.

504
00:22:28,630 --> 00:22:35,680
Allura issa I jkollhom linja ta 'kodiċi li tgħid x = kubu (x).

505
00:22:35,680 --> 00:22:36,930
Allura fil-fatt let's -

506
00:22:41,450 --> 00:22:43,940
il-linja ta 'kodiċi, irtirar, qisu dan.

507
00:22:43,940 --> 00:22:45,960
x = kubu (x).

508
00:22:45,960 --> 00:22:48,100
Allura kif huwa dan se jaħdem?

509
00:22:48,100 --> 00:22:50,820
Mela ejja imorru quddiem u jagħtuk screen abjad mill-ġdid.

510
00:22:50,820 --> 00:22:55,000
U jiena ser jikteb issa l-valur ta 'x, li f'dan il-mument fil-

511
00:22:55,000 --> 00:23:01,080
ħin jiġri li jkun, ejja ngħidu, 2, li jżommha sempliċi.

512
00:23:01,080 --> 00:23:04,890
So I kitbu isfel fuq biċċa karta mill-valur 2,

513
00:23:04,890 --> 00:23:06,100
li hija x-valur tiegħi.

514
00:23:06,100 --> 00:23:08,250
I jagħtiha lill Ken.

515
00:23:08,250 --> 00:23:09,200
KEN: U jien biss jiktbu l-risposta?

516
00:23:09,200 --> 00:23:12,660
DAVID J. Malan: Yeah, ejja biss jiktbu l-risposta.

517
00:23:12,660 --> 00:23:13,030
Okay.

518
00:23:13,030 --> 00:23:16,280
U issa huwa għandu jirritorna lili xi ħaġa.

519
00:23:16,280 --> 00:23:17,560
Allura -

520
00:23:17,560 --> 00:23:18,170
perfetta.

521
00:23:18,170 --> 00:23:18,840
Nizza segue.

522
00:23:18,840 --> 00:23:21,970
>> Allura issa huwa f'idejn me lura l-valur ta '8, f'dan il-każ.

523
00:23:21,970 --> 00:23:23,220
U x'għandi nagħmel miegħu?

524
00:23:23,220 --> 00:23:26,130
Ukoll, fil-fatt, ejja ara.

525
00:23:26,130 --> 00:23:26,640
Get dan id-dritt.

526
00:23:26,640 --> 00:23:27,880
What am I se tagħmel magħha?

527
00:23:27,880 --> 00:23:31,900
Issa jien ser jieħdu dan il-valur u fil-fatt jaħżen fil dawk

528
00:23:31,900 --> 00:23:33,400
bits istess memorja.

529
00:23:33,400 --> 00:23:35,030
Imma l-avviż, jien tip ta 'tissara hawn.

530
00:23:35,030 --> 00:23:38,280
Jien ftit konfuż għaliex fejn nista attwalment tikteb il-valur ta 'x?

531
00:23:38,280 --> 00:23:41,840
Minħabba dak li stajt biss isir huwa fiżikament naħa Ken biċċa karta

532
00:23:41,840 --> 00:23:44,400
li kellha l-valur 2, li kien x.

533
00:23:44,400 --> 00:23:46,300
U fil-fatt, dan huwa preċiżament dak li jiġri.

534
00:23:46,300 --> 00:23:50,100
Għalhekk jirriżulta li meta inti sejħa funzjoni, u inti tgħaddi fl-argument

535
00:23:50,100 --> 00:23:54,130
bħal "bonjour dinja" jew inti tgħaddi fl-argument bħal 2, ġeneralment, int

536
00:23:54,130 --> 00:23:56,720
tgħaddi fil-kopja ta 'dan l-argument.

537
00:23:56,720 --> 00:24:01,020
U hekk biss kif I kiteb isfel in-numru 2 hawn u mogħtija lill Ken; li għandu

538
00:24:01,020 --> 00:24:04,760
jfissirx li għadni kopja ta 'l-2 valur x'imkien.

539
00:24:04,760 --> 00:24:08,140
Minħabba fil-fatt, issa li stajt gotten lura l-valur 8, I bżonn li jmorru lura fil-

540
00:24:08,140 --> 00:24:12,010
RAM u fil-fatt ikteb 8 fejn I ladarba kellhom in-numru 2.

541
00:24:12,010 --> 00:24:15,720
>> Mela ftakar viżwalment dan il-kunċett ta 'tgħaddi fil litteralment

542
00:24:15,720 --> 00:24:16,730
kopja tal-valur.

543
00:24:16,730 --> 00:24:19,570
Ken ma ħaġa tagħha, idejn me lura xi ħaġa - f'dan il-każ,

544
00:24:19,570 --> 00:24:20,820
valur bħal 8.

545
00:24:20,820 --> 00:24:22,660
U mbagħad I għandek tagħmel xi ħaġa ma 'dak il-valur jekk I

546
00:24:22,660 --> 00:24:24,880
tixtieq li jżommha madwar.

547
00:24:24,880 --> 00:24:29,470
Allura dan kollu se jkunu kollha wisq familjari qabel twil.

548
00:24:29,470 --> 00:24:33,082
Grazzi tant għal dan demo hawn, Ken.

549
00:24:33,082 --> 00:24:34,820
Kull dritt.

550
00:24:34,820 --> 00:24:36,720
Tajjeb ħafna x'isir.

551
00:24:36,720 --> 00:24:40,610
Mela ejja ara kif li finalment tirrigwarda xi wħud mill-funzjoni

552
00:24:40,610 --> 00:24:42,270
sejħa li aħna kont qed tagħmel hawn.

553
00:24:42,270 --> 00:24:47,610
So let me go quddiem u jressaqna lura għall-eżempju cubing hawn.

554
00:24:47,610 --> 00:24:53,080
U tinnota li jekk irridu li attwalment tibda tieħu din ulterjuri, aħna qed tmur

555
00:24:53,080 --> 00:24:57,050
li jkollha li tkun konxja tal-fatt li l-x numru li l-jiġu mgħoddija fil

556
00:24:57,050 --> 00:25:01,390
hawnhekk hija differenti minn dak li fil-fatt jiġu mgħoddija fil-funzjoni.

557
00:25:01,390 --> 00:25:03,940
Għalhekk għal darb'oħra, dan għadda minn kopja se jsiru pjuttost

558
00:25:03,940 --> 00:25:05,620
germane fi ftit mument.

559
00:25:05,620 --> 00:25:09,320
>> Mela ejja tagħti ħarsa lejn xi ħaġa li ma pjuttost xogħol tajba s'issa.

560
00:25:09,320 --> 00:25:11,790
Jien ser jimxi 'l quddiem u tiftaħ eżempju Buggy 3, li

561
00:25:11,790 --> 00:25:13,560
huwa difettuż min-natura.

562
00:25:13,560 --> 00:25:18,070
U huwa msejjaħ buggy3, u timplimenta funzjoni iskambji.

563
00:25:18,070 --> 00:25:23,500
Allura hawnhekk għandna funzjoni prinċipali li tkun xuy arbitrarju initialized li

564
00:25:23,500 --> 00:25:24,720
1 u 2, rispettivament.

565
00:25:24,720 --> 00:25:27,590
Aħna jistgħu jużaw GetInt, imma aħna biss bżonn ta 'eżerċizzju sempliċi.

566
00:25:27,590 --> 00:25:29,680
Allura huwa diffiċli kodifikata bħala 1 u 2.

567
00:25:29,680 --> 00:25:35,330
Fil-linji 21 u 22, aħna apparentement jistampa xuy, wieħed għal kull linja.

568
00:25:35,330 --> 00:25:39,620
Imbagħad, fuq il-linja 23, I jitolbu jiena iskambji dawn il-valuri, dot, dot, dot.

569
00:25:39,620 --> 00:25:43,030
I apparentement sejħa funzjoni fl linja 24 imsejjaħ swap

570
00:25:43,030 --> 00:25:44,000
li jieħu żewġ argumenti.

571
00:25:44,000 --> 00:25:46,430
Huwa totalment leġittimu għall-funzjonijiet li jieħdu żewġ argumenti.

572
00:25:46,430 --> 00:25:48,220
Rajna printf jagħmlu dan diġà.

573
00:25:48,220 --> 00:25:50,370
Allura tpartit apparentement tieħu xuy.

574
00:25:50,370 --> 00:25:53,010
U kif ismu jissuġġerixxi, nixtieq tama li huwa għaddej biex

575
00:25:53,010 --> 00:25:54,320
tpartit dawn iż-żewġ valuri.

576
00:25:54,320 --> 00:25:57,560
Allura mbagħad I pretensjoni fuq il-linja 25, biddlu.

577
00:25:57,560 --> 00:26:01,570
U jien Reprint xuy bis-suppożizzjoni li

578
00:26:01,570 --> 00:26:02,830
li ħadthom tabilħaqq biddlu.

579
00:26:02,830 --> 00:26:04,370
Imma jekk I attwalment tmexxi dan il-programm -

580
00:26:04,370 --> 00:26:06,060
let me tiftaħ tieqa terminal.

581
00:26:06,060 --> 00:26:07,750
Let me jagħmlu buggy3.

582
00:26:07,750 --> 00:26:09,970
Kif tissuġġerixxi l-isem, dan mhux se jispiċċaw tajjeb.

583
00:26:09,970 --> 00:26:14,690
Għaliex meta I hit Ikteb, avviż li x hija l-1.

584
00:26:14,690 --> 00:26:15,720
y huwa 2.

585
00:26:15,720 --> 00:26:19,160
And yet fl-aħħar tal-programm, dawn għadhom qed, fil-fatt, l-istess.

586
00:26:19,160 --> 00:26:22,760
>> Allura ibbażata fuq id-dimostrazzjoni biss issa ma Ken, dak li fil-fatt jiġri?

587
00:26:22,760 --> 00:26:24,660
Ukoll, ejja adsa fis din il-funzjoni tpartit.

588
00:26:24,660 --> 00:26:25,800
Huwa super qasir.

589
00:26:25,800 --> 00:26:28,020
Huwa biss ftit linji tal-kodiċi twil.

590
00:26:28,020 --> 00:26:32,810
Imma x'inhu l-problema fundamentali bbażata fuq l-istorja sempliċi told

591
00:26:32,810 --> 00:26:34,270
up hawn ma Ken?

592
00:26:34,270 --> 00:26:36,115
Għaliex maqsuma tpartit huwa?

593
00:26:36,115 --> 00:26:37,365
[Inaudible]

594
00:26:39,840 --> 00:26:40,460
Eżattament.

595
00:26:40,460 --> 00:26:43,610
Allura aħna qed jaħżnu għal kopja, mhux l-varjabbli innifsu.

596
00:26:43,610 --> 00:26:46,810
Fi kliem ieħor, tpartit apparentement jieħu żewġ argumenti, ta 'int.

597
00:26:46,810 --> 00:26:49,370
U huwa arbitrarjament msejjaħ b u.

598
00:26:49,370 --> 00:26:54,430
U up hawn, stajt għaddew fl xuy, li huma rispettivament 1 u 2.

599
00:26:54,430 --> 00:26:56,580
Imma jien ma litteralment jgħaddi fil x.

600
00:26:56,580 --> 00:26:58,410
Jien ma litteralment jgħaddi fil y.

601
00:26:58,410 --> 00:27:01,230
Jien tgħaddi kopja ta 'x u kopja ta' y.

602
00:27:01,230 --> 00:27:05,180
Huwa simili kważi daqs li kieku inti kkupjati u pasted fis tpartit l-valuri li

603
00:27:05,180 --> 00:27:07,440
inti tixtieq li attwalment jimmanipulaw.

604
00:27:07,440 --> 00:27:11,970
Allura jekk dan huwa l-każ, meta I, il-programm, bidu eżekuzzjoni

605
00:27:11,970 --> 00:27:14,140
linja 35, imbagħad 36 -

606
00:27:14,140 --> 00:27:17,740
meta nasal għal-linja 37, f'dan il-punt fl-istorja, dak li huwa l-valur ta '?

607
00:27:20,740 --> 00:27:24,850
Fuq dan il-punt fl-istorja, linja 37, dak li huwa l-valur ta 'f'dan il-punt?

608
00:27:24,850 --> 00:27:25,980
Għalhekk għandu jkun biss 1.

609
00:27:25,980 --> 00:27:26,170
Dritt?

610
00:27:26,170 --> 00:27:29,100
Minħabba x kienet għaddiet fl bħala l-ewwel argument.

611
00:27:29,100 --> 00:27:33,150
U din il-funzjoni biss b'mod arbitrarju qed issejjaħ ewwel argument tagħha,.

612
00:27:33,150 --> 00:27:35,130
Bl-istess mod huwa y, it-tieni argument.

613
00:27:35,130 --> 00:27:37,930
U huwa biss arbitrarju sejħa tal-b tieni argument.

614
00:27:37,930 --> 00:27:40,510
>> Issa din id-dikotomija huwa attwalment pjuttost sempliċi spjegat.

615
00:27:40,510 --> 00:27:40,880
Aħseb dwar dan.

616
00:27:40,880 --> 00:27:42,980
Xejn minna laħqu l-persuna li kiteb printf.

617
00:27:42,980 --> 00:27:49,880
Allura żgur, hu jew hi għandha l-ebda idea liema fatturi varjabbli tagħna 30 snin wara tmur

618
00:27:49,880 --> 00:27:50,710
li għandu jissejjaħ.

619
00:27:50,710 --> 00:27:55,110
Għalhekk għandu jkun hemm distinzjoni bejn dak li inti sejħa varjabbli

620
00:27:55,110 --> 00:27:59,960
funzjonijiet int bil-miktub u dak li inti sejħa varjabbli fil-funzjonijiet int

621
00:27:59,960 --> 00:28:01,770
sejħa jew bl-użu.

622
00:28:01,770 --> 00:28:05,120
Allura fi kliem ieħor, ktibtu varjabbli tiegħi bħala xuy.

623
00:28:05,120 --> 00:28:08,060
Imma jekk xi ħadd ieħor kien kiteb il-funzjoni tpartit, hu jew hi ċertament

624
00:28:08,060 --> 00:28:10,480
ma jkunux jafu liema fatturi varjabbli tiegħi ser ikunu msejħa.

625
00:28:10,480 --> 00:28:13,850
Allura jirrealizzaw li dan huwa għaliex għandek dan duwalità ta 'ismijiet.

626
00:28:13,850 --> 00:28:16,800
Teknikament, I jistgħu jagħmlu dan billi koinċidenza.

627
00:28:16,800 --> 00:28:19,750
Iżda huma xorta waħda tiġi mgħoddija f'numru ta 'kopji.

628
00:28:19,750 --> 00:28:22,940
Ikun biss tkun koinċidenza pur estetikament jekk dik il-persuna li kiteb

629
00:28:22,940 --> 00:28:25,590
tpartit kienet użat l-istess ismijiet.

630
00:28:25,590 --> 00:28:25,930
>> Kull dritt.

631
00:28:25,930 --> 00:28:29,010
Allura f'dan il-punt fl-istorja, linja 37, hija l-1.

632
00:28:29,010 --> 00:28:30,410
b huwa 2.

633
00:28:30,410 --> 00:28:32,040
U issa I tipproċedi biex tpartit lilhom.

634
00:28:32,040 --> 00:28:34,730
Ukoll l-ewwel nett, let me fil-fatt jagħmlu dan ħafna aktar sempliċi.

635
00:28:34,730 --> 00:28:36,500
I do not know dak dawk il-linji 3 tal-kodiċi kienu qed jagħmlu.

636
00:28:36,500 --> 00:28:37,370
Let me biss tagħmel dan.

637
00:28:37,370 --> 00:28:38,850
b gets.

638
00:28:38,850 --> 00:28:40,170
a gets b.

639
00:28:40,170 --> 00:28:41,450
Magħmul.

640
00:28:41,450 --> 00:28:43,540
Għaliex dan imkisser, loġikament?

641
00:28:46,980 --> 00:28:48,590
Huwa tip tal-ħaġa intuwittivi, id-dritt?

642
00:28:48,590 --> 00:28:50,640
Allura isir b.

643
00:28:50,640 --> 00:28:52,450
U b isir.

644
00:28:52,450 --> 00:28:55,410
Iżda l-problema hija li hekk kif linja 37 tesegwixxi, x'inhu l-

645
00:28:55,410 --> 00:28:58,170
valur ta 'u b?

646
00:28:58,170 --> 00:28:59,070
L-istess, 1.

647
00:28:59,070 --> 00:29:03,460
Għaliex inti tkun clobbered, biex ngħidu hekk, inti stajt mibdula b biex ikunu ugwali għal.

648
00:29:03,460 --> 00:29:06,000
Allura ladarba linja 37 hija esegwita, li l-kbir.

649
00:29:06,000 --> 00:29:09,940
Inti issa għandhom żewġ kopji tal-numru 1 ġewwa ta 'din il-funzjoni.

650
00:29:09,940 --> 00:29:14,720
Mela allura meta inti tgħidli fil-linja 38, li gets b, ukoll, int tip ta 'invitat.

651
00:29:14,720 --> 00:29:17,370
Għaliex int biss assenjazzjoni 1 għal 1.

652
00:29:17,370 --> 00:29:20,400
You ħadthom tip ta 'tilfu l-valur inti tajt.

653
00:29:20,400 --> 00:29:22,910
>> Allura fil-verżjoni oriġinali ta 'dan, l-avviż dak li għamilt.

654
00:29:22,910 --> 00:29:26,620
I minflok kellhom tielet linja ta 'kodiċi li dehru qishom dan.

655
00:29:26,620 --> 00:29:29,910
Niddikjara varjabbli temporanju - TMP huwa isem komuni ħafna

656
00:29:29,910 --> 00:29:31,240
għal varjabbli temporanju.

657
00:29:31,240 --> 00:29:34,280
Huwa ta 'int għax irid ikun kompatibbli dak li nixtieq li tagħmel kopja ta'.

658
00:29:34,280 --> 00:29:39,720
I taħżen kopja ta 'ġewwa ta' TMP. Allura ladarba linja 37 tkun wettqet,

659
00:29:39,720 --> 00:29:41,390
il-valur ta 'huwa -

660
00:29:41,390 --> 00:29:42,970
sanità malajr check -

661
00:29:42,970 --> 00:29:43,460
1.

662
00:29:43,460 --> 00:29:45,780
Il-valur ta 'b huwa 2.

663
00:29:45,780 --> 00:29:48,470
U l-valur tal-TMP huwa wkoll 1.

664
00:29:48,470 --> 00:29:51,470
Allura issa I tesegwixxi linja 38.

665
00:29:51,470 --> 00:29:57,180
Allura ladarba linja 38 tesegwixxi, a jieħu l-valur ta 'b.

666
00:29:57,180 --> 00:29:58,510
U b '2.

667
00:29:58,510 --> 00:30:00,500
Allura issa huwa 2.

668
00:30:00,500 --> 00:30:03,110
Allura f'dan il-punt fl-istorja, li huwa 2, b huwa 2,

669
00:30:03,110 --> 00:30:05,130
u TMP huwa 1.

670
00:30:05,130 --> 00:30:09,330
Allura issa loġikament, nistgħu valur eżatt TMP plop s in b.

671
00:30:09,330 --> 00:30:10,690
U aħna qed isir.

672
00:30:10,690 --> 00:30:12,170
>> Allura aħna ve solvuti din il-problema.

673
00:30:12,170 --> 00:30:16,040
Sfortunatament, meta I run dan il-programm f'din il-forma, din attwalment ma tpartit

674
00:30:16,040 --> 00:30:17,700
kwalunkwe valur.

675
00:30:17,700 --> 00:30:18,950
Iżda biex ikunu ċari, għaliex?

676
00:30:23,420 --> 00:30:26,310
I fiss il-problema loġiku minn ftit mument ilu.

677
00:30:26,310 --> 00:30:31,150
Iżda għal darb'oħra, jekk I run dan il-programm, xuy jibqgħu mhux mibdula sa l-aħħar ta '

678
00:30:31,150 --> 00:30:33,834
esekuzzjoni tal-programm.

679
00:30:33,834 --> 00:30:34,760
[Inaudible]

680
00:30:34,760 --> 00:30:36,030
DAVID J. Malan: Allura aħna ma lura xejn.

681
00:30:36,030 --> 00:30:36,960
Allura dan huwa veru.

682
00:30:36,960 --> 00:30:39,880
Iżda jirriżulta hemm daqsxejn ta 'problema hawnhekk għaliex s'issa, ir-

683
00:30:39,880 --> 00:30:42,460
unika ħaġa aħna kont qed kapaċi li jirritornaw hija ħaġa waħda.

684
00:30:42,460 --> 00:30:46,540
U dan huwa restrizzjoni ta 'C. Tista' biss jirritorna verament valur wieħed,

685
00:30:46,540 --> 00:30:48,970
f'liema każ, jien tip ta 'mwaħħla hawn

686
00:30:48,970 --> 00:30:51,805
minħabba I tista 'lura l-valur il-ġdid ta' x jew I tista 'lura l-

687
00:30:51,805 --> 00:30:53,160
valur il-ġdid ta 'y.

688
00:30:53,160 --> 00:30:54,330
Imma nixtieq tnejn lura.

689
00:30:54,330 --> 00:30:58,010
Allura lura mhix is-soluzzjoni sempliċi hawn.

690
00:30:58,010 --> 00:30:59,770
Iżda l-problema fundamentalment huwa għaliex?

691
00:30:59,770 --> 00:31:03,270
Dak li aħna fil-fatt skambjati?

692
00:31:03,270 --> 00:31:04,010
au b.

693
00:31:04,010 --> 00:31:07,670
Iżda aub huma kopji ta 'xuy, li jfisser aħna biss ma kollha ta' dan

694
00:31:07,670 --> 00:31:10,080
xogħol - aħna biss qattgħu bħal tliet minuti jitkellem dwar it-tpartit

695
00:31:10,080 --> 00:31:11,680
funzjoni u t-tlieta ta 'dawn il-varjabbli.

696
00:31:11,680 --> 00:31:15,090
U li l-kbir, perfettament korretta b'mod iżolat.

697
00:31:15,090 --> 00:31:20,230
Iżda u ambitu b s biss huwa f'dawn il-linji hawn.

698
00:31:20,230 --> 00:31:24,130
Hekk biss bħal għal loop, jekk inti tiddikjara integer i ġewwa l-għar

699
00:31:24,130 --> 00:31:27,400
loop - b'mod simili, ġewwa jekk int tiddikjara u b ta 'funzjoni li

700
00:31:27,400 --> 00:31:30,550
inti stajt bil-miktub, dawn qed biss ġewwa validu ta 'dik il-funzjoni.

701
00:31:30,550 --> 00:31:35,020
Li jfisser malli tpartit isir eżekuzzjoni u immorru mil-linja 24 sa

702
00:31:35,020 --> 00:31:38,380
linja 25, xuy ma nbidlux fil-livelli kollha.

703
00:31:38,380 --> 00:31:42,580
Inti biss moħlija lott kollu ta 'żmien jagħmlu skambju kopji ta' fatturi varjabbli.

704
00:31:42,580 --> 00:31:46,490
>> Għalhekk jirriżulta li s-soluzzjoni għal dan huwa attwalment mhux ovvju.

705
00:31:46,490 --> 00:31:49,210
Huwa pjuttost mhux biżżejjed biex jirritornaw valuri għaliex nistgħu

706
00:31:49,210 --> 00:31:50,320
biss ritorn valur wieħed.

707
00:31:50,320 --> 00:31:53,370
U jien verament tixtieq li tpartit kemm xuy fl-istess ħin.

708
00:31:53,370 --> 00:31:55,020
Allura aħna qed tmur biex terga 'lura għal dan.

709
00:31:55,020 --> 00:31:58,770
Iżda għal issa, jirrealizzaw li l-kwistjoni fundamentalment ġejja mill-fatt

710
00:31:58,770 --> 00:32:00,660
li aub huma kopji.

711
00:32:00,660 --> 00:32:03,450
U huma fl-ambitu tagħhom stess.

712
00:32:03,450 --> 00:32:04,980
Ukoll, ejja jippruvaw isolvu din b'xi mod.

713
00:32:04,980 --> 00:32:09,200
Let me attwalment scroll lura hawn u tiftaħ, ejja ngħidu, varjant 4

714
00:32:09,200 --> 00:32:11,170
ta 'dan, buggy4.

715
00:32:11,170 --> 00:32:13,230
U xi ngħidu dwar dan?

716
00:32:13,230 --> 00:32:16,690
Din hija problema simili iżda aktar sempliċi li tħares lejn qabel we tieħu stab fil

717
00:32:16,690 --> 00:32:17,530
jissolvew.

718
00:32:17,530 --> 00:32:19,440
Dan il-programm huwa msejjaħ inkrement.

719
00:32:19,440 --> 00:32:24,320
U apparentement initializes integer x sa 1 fil-linja 18.

720
00:32:24,320 --> 00:32:25,950
I imbagħad titlob x hija l-1.

721
00:32:25,950 --> 00:32:28,020
I imbagħad istqarrija inkrementazzjoni, dot, dot, dot.

722
00:32:28,020 --> 00:32:29,460
I imbagħad call inkrement.

723
00:32:29,460 --> 00:32:33,480
Iżda mbagħad fil-linji 22 u 23, I jitolbu huwa kien inkrementat.

724
00:32:33,480 --> 00:32:37,780
I jsostnu x issa hija tkun xi tkun, preżumibbilment 2.

725
00:32:37,780 --> 00:32:39,770
>> Iżda dan il-programm huwa Buggy.

726
00:32:39,770 --> 00:32:41,020
X'hemm l-problema?

727
00:32:43,450 --> 00:32:44,418
Yeah?

728
00:32:44,418 --> 00:32:45,668
[Inaudible]

729
00:32:49,260 --> 00:32:49,850
DAVID J. Malan: Eżattament.

730
00:32:49,850 --> 00:32:52,430
Allura x ġiet dikjarata ovvjament fuq il-linja 18.

731
00:32:52,430 --> 00:32:54,410
Dan huwa ġewwa ċineg kaboċċi ewlenin tal.

732
00:32:54,410 --> 00:32:58,470
Għalhekk ir-risposta sempliċi hawnhekk hija li, ukoll, x jeżisti hawnhekk.

733
00:32:58,470 --> 00:33:01,510
Ma teżistix fil-linja 32.

734
00:33:01,510 --> 00:33:03,710
Allura dan il-programm fil-fatt mhux saħansitra se jiġbor.

735
00:33:03,710 --> 00:33:07,910
Il-kompilatur, meta nipprova kompilazzjoni ta 'dan il-kodiċi, se Yell fil lili

736
00:33:07,910 --> 00:33:13,190
dwar xi identifikatur mhux dikjarat jew xi ħaġa f'dan is-sens.

737
00:33:13,190 --> 00:33:13,870
Fil-fatt, ejja ipprova.

738
00:33:13,870 --> 00:33:15,235
Dan huwa jagħmel buggy4.

739
00:33:17,780 --> 00:33:18,190
Hemm huwa.

740
00:33:18,190 --> 00:33:22,030
Użu ta 'x identifikatur mhux iddikjarat fil-linja 32.

741
00:33:22,030 --> 00:33:25,700
U fil-fatt, ejja tkun iktar espliċita hawn illum sabiex dan ikun utli fl-

742
00:33:25,700 --> 00:33:27,140
uffiċċju sigħat u fid-dar.

743
00:33:27,140 --> 00:33:29,000
Avviż li huwa ftit cryptically miktub.

744
00:33:29,000 --> 00:33:31,560
Imma l-fatt għandha clang li għajjat ​​fil us, qal

745
00:33:31,560 --> 00:33:36,970
buggy4.c: 32:5, huwa attwalment utli.

746
00:33:36,970 --> 00:33:41,970
Dan ifisser li l-iżball huwa fuq il-linja 32 fil-pożizzjoni karattru 5.

747
00:33:41,970 --> 00:33:44,670
Allura wieħed, tnejn, tlieta, erba ', ħames.

748
00:33:44,670 --> 00:33:46,640
Li, fil-fatt, meta l-problema hija.

749
00:33:46,640 --> 00:33:49,710
U wkoll li wieħed iżomm f'moħħu li ħinijiet tal-uffiċċju u d-dar, jien xxurtjati hawn.

750
00:33:49,710 --> 00:33:50,740
I jkollhom waħda żball.

751
00:33:50,740 --> 00:33:52,660
Huwa ser tkun relattivament faċli biex jiffissaw.

752
00:33:52,660 --> 00:33:56,220
Imma jekk ikollok iskrin kollu sħiħa ta 'messaġġi ta' żball enormi, għal darb'oħra,

753
00:33:56,220 --> 00:33:59,240
jirrealizzaw li l-waħda bottommost jista 'jkun biss sintomatika ta'

754
00:33:59,240 --> 00:34:00,320
dawk topmost.

755
00:34:00,320 --> 00:34:03,560
Hekk dejjem chase stabbiliti bugs tiegħek minn isfel quċċata.

756
00:34:03,560 --> 00:34:06,720
Minħabba li hemm jista 'jkun biss effett daisy-katina li qed tissuġġerixxi int

757
00:34:06,720 --> 00:34:09,030
għandhom problemi mod aktar milli suppost fil-fatt tagħmel.

758
00:34:09,030 --> 00:34:14,989
>> Allura kif nistgħu jiffissaw dan jekk l-għan tiegħi huwa li inkrement x?

759
00:34:14,989 --> 00:34:15,370
X'hemm li?

760
00:34:15,370 --> 00:34:15,620
Okay.

761
00:34:15,620 --> 00:34:16,679
Allura nistgħu nagħmlu x globali.

762
00:34:16,679 --> 00:34:18,860
Ejja jieħdu l-buttuna li I wissiet dwar preċedenti.

763
00:34:18,860 --> 00:34:20,550
Iżda Heck, aħna biss bżonn ta 'jiffissaw malajr.

764
00:34:20,550 --> 00:34:23,949
Mela ejja biss jgħidu x int up here.

765
00:34:23,949 --> 00:34:25,600
Li jagħmel x globali.

766
00:34:25,600 --> 00:34:28,460
Allura issa għandha ewlieni aċċess għalih.

767
00:34:28,460 --> 00:34:31,780
U inkrement għandu aċċess għaliha.

768
00:34:31,780 --> 00:34:33,860
U hekk let me jimxi 'l quddiem u jikkumpilaw dan issa.

769
00:34:33,860 --> 00:34:36,330
Għamla buggy4, Ikteb.

770
00:34:36,330 --> 00:34:37,440
Jidher li jikkompilaw issa.

771
00:34:37,440 --> 00:34:40,949
Ejja run buggy4, u jidher li attwalment jaħdmu.

772
00:34:40,949 --> 00:34:42,780
Issa dan huwa wieħed ta 'dawn l-affarijiet -

773
00:34:42,780 --> 00:34:45,870
do kif ngħid jien, mhux bħala I do, kif stajt biss isir hawn.

774
00:34:45,870 --> 00:34:49,239
Minħabba b'mod ġenerali, programmi tagħna ser jiksbu ħafna aktar interessanti u

775
00:34:49,239 --> 00:34:50,440
ħafna itwal minn dan.

776
00:34:50,440 --> 00:34:53,199
U jekk soluzzjoni tiegħek għall-problemi tal-ħajja huwa biss ah, tpoġġi l-

777
00:34:53,199 --> 00:34:57,550
varjabbli fil-quċċata tal-fajl tiegħek, malajr ħafna do programmi tikseb

778
00:34:57,550 --> 00:34:59,700
horrifically diffiċli biex tamminstrahom.

779
00:34:59,700 --> 00:35:02,050
Jiġrilha diffiċli li wieħed jaħseb up ismijiet varjabbli ġodda.

780
00:35:02,050 --> 00:35:05,240
Jiġrilha diffiċli biex jifhem dak varjabbli qed tagħmel dak.

781
00:35:05,240 --> 00:35:08,250
>> U għalhekk b'mod ġenerali, din mhix soluzzjoni tajba.

782
00:35:08,250 --> 00:35:09,780
Mela ejja tagħmel dan aħjar.

783
00:35:09,780 --> 00:35:11,920
Aħna ma rridux li jużaw varjabbli globali hawn.

784
00:35:11,920 --> 00:35:14,050
I do jridu inkrement x.

785
00:35:14,050 --> 00:35:16,050
So I jistgħu ovvjament -

786
00:35:16,050 --> 00:35:18,450
fl-aħħar tal-ġurnata, huwa tip ta 'storja iblah għaliex aħna biss tagħmel dan.

787
00:35:18,450 --> 00:35:22,050
Imma jekk jien ma taf dwar dak l-operatur, jew I ma kienx permess li

788
00:35:22,050 --> 00:35:27,700
bidla fl prinċipali nfisha, kif inkella jista I timplimenta Ken hawn fuq, dan

789
00:35:27,700 --> 00:35:31,450
żmien li ma kubu iżda li inkrement?

790
00:35:31,450 --> 00:35:32,700
Kif nista 'bidla dan ħaġa hawn?

791
00:35:32,700 --> 00:35:33,025
Yeah.

792
00:35:33,025 --> 00:35:34,275
[Inaudible]

793
00:35:37,430 --> 00:35:38,000
DAVID J. Malan: Okay, tajba.

794
00:35:38,000 --> 00:35:40,490
Allura għaliex ma I jgħaddu fil x?

795
00:35:40,490 --> 00:35:44,390
U allura minflok jirritornaw dan, għaliex ma I biss tagħmel ritorn x + 1?

796
00:35:44,390 --> 00:35:46,370
Issa, l-affarijiet ftit aktar jkollha tinbidel hawnhekk.

797
00:35:46,370 --> 00:35:47,530
Jien fuq il-binarju dritt.

798
00:35:47,530 --> 00:35:48,910
X'iktar għandi bżonn biex tweak?

799
00:35:48,910 --> 00:35:49,470
Xi ħadd ieħor.

800
00:35:49,470 --> 00:35:49,882
Yeah?

801
00:35:49,882 --> 00:35:51,530
[Inaudible]

802
00:35:51,530 --> 00:35:53,520
DAVID J. Malan: I ħtieġa li tinbidel it-tip ritorn ta 'inkrement

803
00:35:53,520 --> 00:35:54,590
għaliex mhuwiex null.

804
00:35:54,590 --> 00:35:56,650
Null tfisser xejn l-jiġu rritornati.

805
00:35:56,650 --> 00:35:57,600
Iżda b'mod ċar, issa huwa.

806
00:35:57,600 --> 00:36:01,280
Allura dan jeħtieġ li tinbidel li int tkun konsistenti ma 'kwalunkwe

807
00:36:01,280 --> 00:36:02,580
Jien fil-fatt jirritornaw.

808
00:36:02,580 --> 00:36:04,580
>> Issa xi ħaġa oħra għadu Buggy hawn.

809
00:36:04,580 --> 00:36:04,982
Yeah?

810
00:36:04,982 --> 00:36:06,590
[Inaudible]

811
00:36:06,590 --> 00:36:07,630
DAVID J. Malan: So I bżonn biex inkrement x?

812
00:36:07,630 --> 00:36:10,336
[Inaudible]

813
00:36:10,336 --> 00:36:11,880
DAVID J. Malan: Ah, so I bżonn li tgħaddi x.

814
00:36:11,880 --> 00:36:13,300
So I bżonn tagħmel dan hawn.

815
00:36:17,590 --> 00:36:19,690
Allura l-prototip, għandi jibdlu dan up here.

816
00:36:19,690 --> 00:36:21,290
Allura dan għandu jsir int.

817
00:36:21,290 --> 00:36:22,820
Dan għandu jsir -

818
00:36:22,820 --> 00:36:23,670
HMM.

819
00:36:23,670 --> 00:36:24,710
I attwalment jkollhom bug stabbiliti hawn.

820
00:36:24,710 --> 00:36:25,780
Ejja jiffissaw dan ewwel waħda.

821
00:36:25,780 --> 00:36:27,990
X'għandu dan fil-fatt tkun?

822
00:36:27,990 --> 00:36:29,330
Għalhekk huwa ltqajna biex tkun xi ħaġa int.

823
00:36:29,330 --> 00:36:30,340
Jista 'jkun x.

824
00:36:30,340 --> 00:36:33,120
Iżda franchement, jekk tibda ssejjaħ kollha ta 'x varjabbli tiegħek, li għaddej biex tikseb

825
00:36:33,120 --> 00:36:35,250
inqas u inqas ċara li huwa li.

826
00:36:35,250 --> 00:36:38,210
Mela ejja biss b'mod arbitrarju jagħżlu konvenzjoni ismijiet differenti għall tiegħi

827
00:36:38,210 --> 00:36:40,220
helper funzjonijiet, il-funzjonijiet jien bil-miktub.

828
00:36:40,220 --> 00:36:41,100
Aħna ser sejħa hija.

829
00:36:41,100 --> 00:36:44,500
Jew nistgħu sejħa hija - ejja sejħa hija even_number li jkun aktar espliċitu.

830
00:36:44,500 --> 00:36:47,610
Allura mbagħad I jkollhom jirritornaw irrispettivament min-numru huwa plus 1.

831
00:36:47,610 --> 00:36:49,720
U issa għandi jibdlu ħaġa waħda oħra up hawn u wieħed

832
00:36:49,720 --> 00:36:50,700
Ħaġa oħra up here.

833
00:36:50,700 --> 00:36:54,150
What do I għandhom jibdlu fuq il-linja 21 l-ewwel?

834
00:36:54,150 --> 00:36:55,390
Għandi biex tassenja lill x.

835
00:36:55,390 --> 00:36:57,480
So I ma tistax biss sejħa x inkrement.

836
00:36:57,480 --> 00:37:01,000
I bżonn li wieħed jiftakar ir-risposta billi jinbidel il-valur ta 'x fuq

837
00:37:01,000 --> 00:37:02,020
ix-xellug idejn.

838
00:37:02,020 --> 00:37:04,930
U anki jekk x issa hija fuq ix-xellug u tal-lemin, li l-totalment multa minħabba

839
00:37:04,930 --> 00:37:08,370
il-lemin gets esegwiti ewwel imbagħad gets plopped fil-xellug

840
00:37:08,370 --> 00:37:10,240
Ħaġa idejn, x f'dan il-każ.

841
00:37:10,240 --> 00:37:11,900
U mbagħad fl-aħħarnett, din hija tiffissa faċli issa.

842
00:37:11,900 --> 00:37:15,080
Dan għandu biss jaqblu x'hemm stabbiliti hawn taħt.

843
00:37:15,080 --> 00:37:17,120
Int numru.

844
00:37:17,120 --> 00:37:17,320
>> Kull dritt.

845
00:37:17,320 --> 00:37:20,290
Allura mazz sħiħ ta 'bidliet għal funzjoni verament stupid.

846
00:37:20,290 --> 00:37:24,250
Imma rappreżentant ta 'l-affarijiet li aħna ser dejjem trid tagħmel.

847
00:37:24,250 --> 00:37:25,490
Sabiex tagħmel buggy4.

848
00:37:25,490 --> 00:37:26,485
Stajt invitat up x'imkien.

849
00:37:26,485 --> 00:37:27,520
Oh my God.

850
00:37:27,520 --> 00:37:29,660
Ħames żbalji fi, simili, programm ta 'sitt linja.

851
00:37:29,660 --> 00:37:36,500
Allura x'hemm ħażin fuq il-linja 18, il-karattru 5?

852
00:37:36,500 --> 00:37:36,970
Kull dritt.

853
00:37:36,970 --> 00:37:39,330
So I għandhom jiddikjaraw dan int.

854
00:37:39,330 --> 00:37:39,630
Kull dritt.

855
00:37:39,630 --> 00:37:41,790
Mela ejja ara, mazz sħiħ ta 'żbalji oħra.

856
00:37:41,790 --> 00:37:42,230
Oh my god.

857
00:37:42,230 --> 00:37:43,880
19, 18, 21.

858
00:37:43,880 --> 00:37:46,020
Iżda għal darb'oħra, ejja biss ċar l-iskrin -

859
00:37:46,020 --> 00:37:48,660
L Kontroll hawn - u ri-run clang.

860
00:37:48,660 --> 00:37:51,340
Allura 5 problemi hija attwalment biss li wieħed.

861
00:37:51,340 --> 00:37:53,500
Allura issa ejja jimxu buggy4, Ikteb.

862
00:37:53,500 --> 00:37:54,150
Whew.

863
00:37:54,150 --> 00:37:57,434
x ġiet inkrementat korrett.

864
00:37:57,434 --> 00:37:58,420
>> Kull dritt.

865
00:37:58,420 --> 00:38:01,700
Kwalunkwe mistoqsijiet dwar kif inkrement numri?

866
00:38:01,700 --> 00:38:02,896
Yeah?

867
00:38:02,896 --> 00:38:06,864
SPEAKER 2: Għaliex huwa li inti tista 'biss bidla x-numru fil-varjabbli

868
00:38:06,864 --> 00:38:08,860
isem u inneħħu jafu dak li jfisser?

869
00:38:08,860 --> 00:38:09,600
DAVID J. Malan: Mistoqsija tajba.

870
00:38:09,600 --> 00:38:13,130
Kif huwa li nista 'biss bidla x-numru u l-programm se jkun jaf

871
00:38:13,130 --> 00:38:13,990
immedjatament?

872
00:38:13,990 --> 00:38:16,120
Għalhekk għal darb'oħra, think minnha bħala dan estrazzjoni.

873
00:38:16,120 --> 00:38:20,110
Mela jekk jiena prinċipali u Ken huwa inkrementali, franchement, jien ma 'kura

874
00:38:20,110 --> 00:38:21,540
dak Ken sejħiet iPad tiegħu.

875
00:38:21,540 --> 00:38:25,350
I ma kura dak li huwa jsejjaħ kwalunkwe ħaġa li għandha x'taqsam ma 'l-implimentazzjoni tiegħu

876
00:38:25,350 --> 00:38:26,550
ta 'din il-funzjonalità.

877
00:38:26,550 --> 00:38:32,130
Allura dan huwa dettall implimentazzjoni li jien, prinċipali, ma

878
00:38:32,130 --> 00:38:33,010
jkollhom jimpurtahom.

879
00:38:33,010 --> 00:38:37,440
U għalhekk sempliċiment jinbidlu b'mod konsistenti ġewwa tal-funzjoni, numru hawnhekk

880
00:38:37,440 --> 00:38:41,340
u n-numru hawnhekk, hija kollha li tieħu sakemm I recompile.

881
00:38:41,340 --> 00:38:43,820
Huwa tip ta 'bħal jekk inti taħseb dwar - ħafna minna, dawk tal inti ma sewwieq

882
00:38:43,820 --> 00:38:46,590
liċenzji li stajt misjuqa, jew jekk inti ħadthom anke misjuqa fil-karozza -

883
00:38:46,590 --> 00:38:50,710
ħafna minna għandna ebda idea kif taħdem karozza minn taħt il-barnuża.

884
00:38:50,710 --> 00:38:54,710
U litteralment, jekk inti tiftaħ il-barnuża, ħafna minna - myself inklużi -

885
00:38:54,710 --> 00:38:56,580
mhumiex ser verament jafu dak li aħna qed tfittex fuq.

886
00:38:56,580 --> 00:38:58,850
Tip ta 'bħal inti tista' tħossok ma għalf bħal dan id-dritt issa.

887
00:38:58,850 --> 00:39:01,380
Iżda aħna ma verament ikollhom kura kif il-karozza taħdem.

888
00:39:01,380 --> 00:39:05,000
Aħna ma jkollhom kura liema kollha ta 'l vireg u l-pistuni u kejbils ġewwa ta

889
00:39:05,000 --> 00:39:07,700
il-karozza huma fil-fatt jagħmlu.

890
00:39:07,700 --> 00:39:11,360
>> Allura xi ħaġa bħal dak li inti sejħa-pistun ma jimpurtax

891
00:39:11,360 --> 00:39:11,920
hawn f'dan il-każ.

892
00:39:11,920 --> 00:39:12,490
Istess idea.

893
00:39:12,490 --> 00:39:12,670
Yeah?

894
00:39:12,670 --> 00:39:13,920
[Inaudible]

895
00:39:25,250 --> 00:39:29,530
DAVID J. Malan: Jekk kien hemm użi iktar tal-mument xa varjabbli ilu,

896
00:39:29,530 --> 00:39:32,220
int, l-programmer, ikollhom dawn jitbiddlu kullimkien.

897
00:39:32,220 --> 00:39:35,230
Jew inti tista 'litteralment tagħmel, File Menu, u mbagħad Sib / Ibdel,

898
00:39:35,230 --> 00:39:36,270
xi ħaġa bħal dik.

899
00:39:36,270 --> 00:39:40,110
Imma inti se jkollu jagħmel dawk il-bidliet lilek innifsek.

900
00:39:40,110 --> 00:39:41,200
Int għandek tkun konsistenti.

901
00:39:41,200 --> 00:39:42,450
[Inaudible]

902
00:39:47,200 --> 00:39:48,960
DAVID J. Malan: A ordni partikolari bħal hawn?

903
00:39:48,960 --> 00:39:52,660
Jekk dan kien int numru ieħor?

904
00:39:52,660 --> 00:39:52,940
Yeah.

905
00:39:52,940 --> 00:39:56,430
Allura ordni kwistjonijiet meta qed iċċempel l-funzjoni.

906
00:39:56,430 --> 00:40:00,350
Mela jekk jien kienu sejħa inkrement hawn ma 'xi ħaġa virgola xi ħaġa,

907
00:40:00,350 --> 00:40:01,400
hemm immappjar dirett.

908
00:40:01,400 --> 00:40:04,490
Il-varjabbli 1, ikun x'ikun huwa msejjaħ, huwa magħmul kopja tal-ewwel

909
00:40:04,490 --> 00:40:05,480
argument hawn fuq.

910
00:40:05,480 --> 00:40:07,280
Jiddispjacini, dan m'għandux ikun parentesi.

911
00:40:07,280 --> 00:40:09,300
Il-linji argument 2 sa ma t-tieni waħda.

912
00:40:09,300 --> 00:40:11,220
>> Allura ordni, iva, il-kwistjonijiet.

913
00:40:11,220 --> 00:40:11,490
Kull dritt.

914
00:40:11,490 --> 00:40:13,360
Jiddispjacini I ħa triq twila biex naslu s'hemm.

915
00:40:13,360 --> 00:40:14,610
Mistoqsijiet oħra?

916
00:40:16,460 --> 00:40:16,850
Kull dritt.

917
00:40:16,850 --> 00:40:20,300
Mela ejja ara jekk ma nkunux nistgħu żebgħa stampa ta 'dak li attwalment għaddejjin

918
00:40:20,300 --> 00:40:22,160
hawn taħt il-barnuża, biex ngħidu hekk.

919
00:40:22,160 --> 00:40:26,310
Allura dan huwa rettangolu li jistgħu jirrappreżentaw memorja tal-kompjuter tiegħek.

920
00:40:26,310 --> 00:40:31,240
Għalhekk anki jekk ma jkollok ebda idea kif memorja xogħlijiet jew kif taħdem RAM, mill-inqas

921
00:40:31,240 --> 00:40:33,590
jassumi li inti għandek għenieqed ta 'dan dawn il-jiem.

922
00:40:33,590 --> 00:40:34,740
You ħadthom ltqajna megabytes ta 'dan.

923
00:40:34,740 --> 00:40:35,760
You ħadthom ltqajna gigabytes ta 'dan.

924
00:40:35,760 --> 00:40:40,690
U nafu minn żero ġimgħa li byte huwa biss dak?

925
00:40:40,690 --> 00:40:41,280
8 bits.

926
00:40:41,280 --> 00:40:42,730
Dritt, hekk 8 zeroes u dawk.

927
00:40:42,730 --> 00:40:46,300
Allura jekk il-kompjuter tiegħek għandha GIG ta 'RAM, żewġ gigs ta' RAM dawn il-jiem, għandek

928
00:40:46,300 --> 00:40:54,450
biljun jew 2 biljun bytes tal-memorja, jew madwar 8 biljun jew 16000000000

929
00:40:54,450 --> 00:40:56,560
bits, ġewwa tal-kompjuter tiegħek.

930
00:40:56,560 --> 00:40:59,710
Issa kuntrarjament għall-eżempju Willy ftit sufi, mhuwiex partiċelli manjetiċi

931
00:40:59,710 --> 00:41:00,560
tipikament aktar.

932
00:41:00,560 --> 00:41:04,470
Dejjem aktar, fil-laptops inqas, huwa drives stat solidu, SSDs, li

933
00:41:04,470 --> 00:41:05,560
biss jkollhom l-ebda partijiet li jiċċaqalqu.

934
00:41:05,560 --> 00:41:06,710
Dan kollu elettroniku.

935
00:41:06,710 --> 00:41:08,070
Dan kollu elettriku bbażata.

936
00:41:08,070 --> 00:41:12,360
Allura taħseb, għalkemm, ta 'dan ir-rettangolu biss bħala li tirrappreżenta l-waħda jew tnejn

937
00:41:12,360 --> 00:41:13,930
gigabytes ta 'memorja li għandek.

938
00:41:13,930 --> 00:41:15,500
>> Allura huwa ta 'blokki ta' memorja.

939
00:41:15,500 --> 00:41:20,460
Issa l-dinja tax-xjenza tal-kompjuter għandu tip ta 'biċċiet maqsum off ta'

940
00:41:20,460 --> 00:41:22,570
memorja biex tagħmel affarijiet differenti.

941
00:41:22,570 --> 00:41:25,930
Għalhekk per eżempju, jekk dan huwa RAM kompjuter tiegħek - kif issuġġerit mill-

942
00:41:25,930 --> 00:41:30,400
rettangolu hemm - jirriżulta li permezz tal-konvenzjoni, fil-quċċata ta 'RAM tiegħek, sabiex

943
00:41:30,400 --> 00:41:33,170
biex ngħidu hekk, huwa ġeneralment dak li sejjaħ segment test.

944
00:41:33,170 --> 00:41:35,910
Dawn huma l-zeroes u dawk li inti għandek miġbura.

945
00:41:35,910 --> 00:41:39,040
Allura meta aħna ve ħares taħt il-barnuża lejn dak a.out hija, kollha

946
00:41:39,040 --> 00:41:40,360
l zeroes u dawk -

947
00:41:40,360 --> 00:41:44,000
meta inti tmexxi programm, dawk zeroes u dawk huma mgħobbija minn drive tiegħek

948
00:41:44,000 --> 00:41:46,290
drive fis xi ħaġa imsejħa RAM.

949
00:41:46,290 --> 00:41:48,950
U fil-RAM, dawn qed tpoġġi fil-quċċata.

950
00:41:48,950 --> 00:41:50,330
Issa sadanittant, inti għandek affarijiet oħra.

951
00:41:50,330 --> 00:41:53,060
Data initialized, data uninitialized.

952
00:41:53,060 --> 00:41:56,440
Dawk swaths 2 ta 'memorja jirreferu għall-varjabbli globali, li

953
00:41:56,440 --> 00:41:57,530
inti ma spiss jużaw.

954
00:41:57,530 --> 00:42:00,630
Imma kultant jekk inti tagħmel, huma jispiċċaw up hemm ukoll.

955
00:42:00,630 --> 00:42:01,620
Imbagħad hemm xi għalf ieħor.

956
00:42:01,620 --> 00:42:04,130
Ambjent varjabbli, li aħna mhux se jqattgħu ħafna ħin fuq.

957
00:42:04,130 --> 00:42:06,120
Iżda mbagħad żewġ affarijiet importanti li se terga 'lura matul dan

958
00:42:06,120 --> 00:42:08,130
, semestru munzell u borġ.

959
00:42:08,130 --> 00:42:12,280
>> Għalhekk ħafna mill-memorja tal-kompjuter tiegħek huwa rriservat meta tmexxija ta 'programm għall-

960
00:42:12,280 --> 00:42:14,880
xi ħaġa imsejjaħ il-munzell u xi ħaġa imsejjaħ il-borġ.

961
00:42:14,880 --> 00:42:16,940
U aħna ma tkunx qed tmur biex jitkellmu dwar il-borġ llum, iżda aħna se

962
00:42:16,940 --> 00:42:18,180
jitkellmu dwar il-munzell.

963
00:42:18,180 --> 00:42:22,910
U l-munzell huwa maħsub li jevokaw l-viżwali ta bħall-sala dining

964
00:42:22,910 --> 00:42:26,120
trejs ikla fil Mather House, jew kull meta inti jiġri li jkun, fejn il-

965
00:42:26,120 --> 00:42:27,810
dining sala persunal nadif minnhom kuljum.

966
00:42:27,810 --> 00:42:30,180
Huma munzell up mill-art fuq up.

967
00:42:30,180 --> 00:42:33,800
U bl-istess mod fil-memorja, hemm din l-idea ta 'tqegħid xi ħaġa fuq

968
00:42:33,800 --> 00:42:36,740
munzell, tqegħid xi ħaġa fuq munzell, tqegħid xi ħaġa fuq munzell.

969
00:42:36,740 --> 00:42:38,000
U dak li rridu nfissru minn dan?

970
00:42:38,000 --> 00:42:41,430
Ukoll, ejja zoom fl fuq ftit-parti t'isfel ta 'din l-istampa, l-kompjuter tiegħek

971
00:42:41,430 --> 00:42:43,990
RAM, tipproponi dan li ġej.

972
00:42:43,990 --> 00:42:48,300
Jirriżulta li meta inti tmexxi programm bħal a.out jew hello, tkun xi tkun

973
00:42:48,300 --> 00:42:49,920
il-programm huwa li inti stajt bil-miktub,

974
00:42:49,920 --> 00:42:53,030
għal darb'oħra, dawk zeroes u dawk huma mgħobbija mill-hard drive tiegħek - li huwa

975
00:42:53,030 --> 00:42:56,190
ħażna fit-tul, jibqa hemmhekk anki meta inti iġbed il-plagg -

976
00:42:56,190 --> 00:42:57,220
mgħobbija fil RAM.

977
00:42:57,220 --> 00:42:59,020
RAM huwa aktar mgħaġġel milli hard drives.

978
00:42:59,020 --> 00:43:00,700
Huwa iżgħar minn hard drives.

979
00:43:00,700 --> 00:43:03,490
Iżda huwa fejn programmi live waqt li tkun qed taħdem fuqhom.

980
00:43:03,490 --> 00:43:06,380
>> Allura inti ikklikkja darbtejn programm fuq Mac jew PC - huwa mgħobbi minn

981
00:43:06,380 --> 00:43:07,750
hard drive fis-RAM.

982
00:43:07,750 --> 00:43:11,760
Hekk kif huwa jitgħabbew fil-RAM, il zeroes u dawk jmorru fil-quċċata mod, il-

983
00:43:11,760 --> 00:43:13,130
hekk imsejħa segment test.

984
00:43:13,130 --> 00:43:17,040
Iżda mbagħad hekk kif program tiegħek attwalment tibda taħdem, il-prinċipali

985
00:43:17,040 --> 00:43:18,140
funzjoni tissejjaħ.

986
00:43:18,140 --> 00:43:21,070
U prinċipali, kif aħna stajt tidher, ta 'spiss ikollu varjabbli lokali.

987
00:43:21,070 --> 00:43:24,560
U għandu ints u kordi u Chars u simili.

988
00:43:24,560 --> 00:43:28,300
Mela jekk program tiegħek li għandek bil-miktub jew il-programm li għandek

989
00:43:28,300 --> 00:43:33,680
double għafast użat xi varjabbli ġewwa ta 'prinċipali, huma jispiċċaw fil-

990
00:43:33,680 --> 00:43:37,020
qiegħ tal tiegħek munzell ta 'memorja, biex ngħidu hekk.

991
00:43:37,020 --> 00:43:39,160
Issa aktar konkret, dak ma dan fil-fatt jfisser?

992
00:43:39,160 --> 00:43:44,080
Dan sempliċiment ifisser li jekk konna se jinnumera l-affarijiet -

993
00:43:44,080 --> 00:43:49,380
jekk konna se numru l-bytes ta 'RAM fil-kompjuter tiegħek, avviż li

994
00:43:49,380 --> 00:43:51,650
dan jista 'jkun żero numru byte.

995
00:43:51,650 --> 00:43:56,130
Dan jista 'jkun in-numru byte wieħed, tnejn, tlieta, erba', ħames, sitt, kollha

996
00:43:56,130 --> 00:43:57,290
il-mod sa biex simili -

997
00:43:57,290 --> 00:44:01,520
2000000000 tkun it-triq kollha up hemm fil-quċċata.

998
00:44:01,520 --> 00:44:05,960
Allura fi kliem ieħor, meta nitkellmu dwar RAM jew memorja f'termini ta 'bytes, huwa

999
00:44:05,960 --> 00:44:09,680
ifisser biss li xi ħadd iddeċieda dak li jinnumera kull

1000
00:44:09,680 --> 00:44:11,110
dawk biċċiet ta 'memorja.

1001
00:44:11,110 --> 00:44:16,950
>> Allura meta għandek bżonn 32 bits għal int, jew għandek bżonn 8 bits għal char, fejn

1002
00:44:16,950 --> 00:44:18,320
ma huma jispiċċaw fil-memorja?

1003
00:44:18,320 --> 00:44:20,650
Ukoll kunċettwali, huma biss jispiċċaw fil-qiegħ ta 'din

1004
00:44:20,650 --> 00:44:21,780
ħaġa imsejjaħ il-munzell.

1005
00:44:21,780 --> 00:44:25,670
Imma x'hemm interessanti issa huwa meta jitlob prinċipali funzjoni.

1006
00:44:25,670 --> 00:44:28,830
Ejja ngħidu funzjoni msejħa foo, biss l-isem arbitrarja.

1007
00:44:28,830 --> 00:44:32,480
Dak li jiġri huwa ewlenija hija fil-qiegħ ta 'dan munzell ta' memorja.

1008
00:44:32,480 --> 00:44:35,630
Foo issa titqiegħed fuq quċċata ta 'prinċipali fil-memorja.

1009
00:44:35,630 --> 00:44:40,020
Allura xi varjazzjonijiet lokali li foo ikun jispiċċaw tip ta 'konċettwalment hawn fuq

1010
00:44:40,020 --> 00:44:40,770
dawk fl prinċipali.

1011
00:44:40,770 --> 00:44:46,920
Jekk foo jitlob funzjoni oħra msejħa bar, dawk il-varjabbli jispiċċaw here.

1012
00:44:46,920 --> 00:44:49,790
Jekk bar jitlob xi ħaġa oħra, hawn, hawn, hawn.

1013
00:44:49,790 --> 00:44:53,900
Allura x'hemm interessanti dwar tmexxija ta 'programm huwa li kif inti sejħa funzjonijiet,

1014
00:44:53,900 --> 00:44:57,720
u kif dawk il-funzjonijiet sejħa funzjonijiet, u kif dawk il-funzjonijiet sejħa funzjonijiet,

1015
00:44:57,720 --> 00:45:00,980
inti jibnu din munzell ta 'funzjonijiet fil-memorja.

1016
00:45:00,980 --> 00:45:06,740
U darba biss ta 'prospetti funzjoni ma tibda jkollna li l-memorja lura.

1017
00:45:06,740 --> 00:45:11,190
Allura wieħed mill-modi eħfef biex jispiċċaw ta 'memorja fil-programm tal-kompjuter hija li

1018
00:45:11,190 --> 00:45:14,170
jiktbu funzjonijiet li qatt ma ritorn.

1019
00:45:14,170 --> 00:45:16,650
>> Għalhekk per eżempju, ejja juru kemm ma '

1020
00:45:16,650 --> 00:45:18,460
intenzjonalment Buggy programm.

1021
00:45:18,460 --> 00:45:24,690
Let me imorru quddiem u jagħmlu # jinkludu <stdio.h>, prinċipali int (vojt).

1022
00:45:24,690 --> 00:45:31,270
U jien ser tagħmel filwaqt li (2> 1), li probabilment mhux se qatt

1023
00:45:31,270 --> 00:45:33,370
bidla fuqna.

1024
00:45:33,370 --> 00:45:37,720
U let me imorru quddiem issa u jagħmlu printf.

1025
00:45:37,720 --> 00:45:39,950
Fil-fatt, li għaddej biex tkun inqas viżwalment interessanti.

1026
00:45:39,950 --> 00:45:40,460
Ejja nagħmlu dan.

1027
00:45:40,460 --> 00:45:44,840
Għal int (i = 0; i> 0).

1028
00:45:44,840 --> 00:45:49,740
Ejja jagħmlu dan l-iżball, i + +.

1029
00:45:49,740 --> 00:45:51,150
U ejja ma printf hawn.

1030
00:45:51,150 --> 00:45:52,550
Ejja prattika dak I kien jippriedka.

1031
00:45:52,550 --> 00:45:54,090
Ejja jkollhom metodu hawn.

1032
00:45:54,090 --> 00:46:00,860
Kor null, u aħna ser ngħidu int i.

1033
00:46:00,860 --> 00:46:02,295
U mbagħad jien se ngħid, printf -

1034
00:46:04,871 --> 00:46:06,790
oh, ejja tagħmel dan aktar interessanti.

1035
00:46:06,790 --> 00:46:08,350
Ejja fil-fatt ma print xejn affattu.

1036
00:46:08,350 --> 00:46:10,530
Ejja biss tagħmel dan.

1037
00:46:10,530 --> 00:46:11,780
Chorus (i).

1038
00:46:16,630 --> 00:46:17,000
>> Kull dritt.

1039
00:46:17,000 --> 00:46:20,040
Allura dan huwa Buggy għaliex għaliex?

1040
00:46:20,040 --> 00:46:22,850
Jien jagħmlu dan up bħala mmur minħabba li l-programm ma attwalment tagħmel xejn

1041
00:46:22,850 --> 00:46:23,420
ta 'interess.

1042
00:46:23,420 --> 00:46:24,670
Iżda li mhux l-għan.

1043
00:46:24,670 --> 00:46:30,440
Il-mira hija li jikteb programm li funzjoni prinċipali ma dak, apparentement?

1044
00:46:30,440 --> 00:46:31,370
Sejħa innifsu.

1045
00:46:31,370 --> 00:46:32,600
U fil-fatt, ma kellniex bżonn il-linja.

1046
00:46:32,600 --> 00:46:36,070
Ejja anki tissimplifika dan biss sabiex ma nitilfu l tassew l-

1047
00:46:36,070 --> 00:46:37,310
fundamentali bug.

1048
00:46:37,310 --> 00:46:39,200
Jistieden ewlenin kor nijet xi kor.

1049
00:46:39,200 --> 00:46:41,760
Imbagħad għamilt xi ħaġa stupid, u kelli kor sejħa kor minħabba I jassumi

1050
00:46:41,760 --> 00:46:43,550
xi ħadd ieħor kien se timplimentaha forsi.

1051
00:46:43,550 --> 00:46:45,960
U issa dan mhux se tiġbor s'issa.

1052
00:46:45,960 --> 00:46:48,340
I-ħtieġa li jagħmlu dak?

1053
00:46:48,340 --> 00:46:49,700
I bżonn l-prototip, tiftakar.

1054
00:46:49,700 --> 00:46:55,520
So I jeħtieġ li jkollhom up hawn kor nulli (int i);.

1055
00:46:55,520 --> 00:46:57,470
>> Allura issa, jekk jien jinżlu hawn -

1056
00:46:57,470 --> 00:46:59,030
fil-fatt, ejja tuża l-tieqa akbar.

1057
00:46:59,030 --> 00:47:01,670
Ejja jimxi 'l quddiem u jagħmlu kor.

1058
00:47:01,670 --> 00:47:06,000
Ejja jimxi 'l quddiem u jagħmlu kor.

1059
00:47:06,000 --> 00:47:08,302
Użu ta 'dikjaratur mhux identifikati i.

1060
00:47:08,302 --> 00:47:09,860
Oh, li kien stupid.

1061
00:47:09,860 --> 00:47:11,020
M'għandniex bżonn l-argument.

1062
00:47:11,020 --> 00:47:13,680
Ejja biss tagħmel dan.

1063
00:47:13,680 --> 00:47:14,550
Jixtiequ kellna beda dan il-mod.

1064
00:47:14,550 --> 00:47:16,160
Kien ikun ta 'programm ħafna aktar faċli biex jiktbu.

1065
00:47:16,160 --> 00:47:20,100
Allura hemm.

1066
00:47:20,100 --> 00:47:23,870
Issa ejja jmorru fuq l terminal tieqa tiegħi, mill-ġdid run clang.

1067
00:47:23,870 --> 00:47:26,900
U hawn we go.

1068
00:47:26,900 --> 00:47:28,020
Dan kien verament mgħaġġel.

1069
00:47:28,020 --> 00:47:30,690
Dak li fil-fatt ġara biss, għalkemm?

1070
00:47:30,690 --> 00:47:33,430
Well, issa I ser żid il-linja istampar, hekk nistgħu naraw.

1071
00:47:33,430 --> 00:47:41,330
So let me say printf, ejja ngħidu, jien fil hawn.

1072
00:47:41,330 --> 00:47:43,470
Okay, l-ebda varjabbli, aħna ser jitilqu minnu bħal dik.

1073
00:47:43,470 --> 00:47:44,860
Let me jerġa 'jsir jagħmlu.

1074
00:47:44,860 --> 00:47:47,940
Let me-ripetizzjoni kor.

1075
00:47:47,940 --> 00:47:51,235
U come fuq.

1076
00:47:53,880 --> 00:47:55,130
Żomm għaddejjin.

1077
00:47:57,630 --> 00:47:59,750
Bħala twarrib, għaliex ma ma ġġarraf għadhom?

1078
00:47:59,750 --> 00:48:02,050
It-tort segmentazzjoni ġara super fast qabel.

1079
00:48:02,050 --> 00:48:04,250
[Inaudible]

1080
00:48:04,250 --> 00:48:04,830
DAVID J. Malan: Eżattament.

1081
00:48:04,830 --> 00:48:06,350
Allura tieħu ż-żmien biex jistampaw.

1082
00:48:06,350 --> 00:48:08,370
Hija biss jieħu aktar xogħol min-naħa tal-kompjuter.

1083
00:48:08,370 --> 00:48:09,550
U hemm hu.

1084
00:48:09,550 --> 00:48:10,620
Tort Segmentazzjoni.

1085
00:48:10,620 --> 00:48:12,140
>> Allura avviż kemm programmi fast run.

1086
00:48:12,140 --> 00:48:14,110
Jekk int ma istampar xejn, super fast.

1087
00:48:14,110 --> 00:48:18,100
Iżda aħna għadhom kisbu dan tort segmentazzjoni għaliex dak li kien qed jiġri?

1088
00:48:18,100 --> 00:48:21,310
Ukoll, jekk inti taħseb dwar kif memorja tal-kompjuter tiegħek hija stabbilita, din

1089
00:48:21,310 --> 00:48:22,890
jiġri li jkun prinċipali.

1090
00:48:22,890 --> 00:48:23,800
Imma hawn -

1091
00:48:23,800 --> 00:48:28,670
ejja biss sejħa dan kor, u ejja sejħa dan kor.

1092
00:48:28,670 --> 00:48:33,420
U issa jekk jien estetika tiegħi dritt, dan huwa biss se ngħid kor,

1093
00:48:33,420 --> 00:48:38,060
kor, kor, kor, kor, kor, kor, nauseum ad.

1094
00:48:38,060 --> 00:48:39,920
U eventwalment, dak li jiġri?

1095
00:48:39,920 --> 00:48:46,690
Jekk l-istampa kbar litteralment huwa dan, dak li jiġri biss konċettwalment?

1096
00:48:46,690 --> 00:48:48,320
Il-eċċessi munzell l-munzelli.

1097
00:48:48,320 --> 00:48:52,400
Jew agħar, inti biss eċċess kollox, inkluż il-segment test, li huwa

1098
00:48:52,400 --> 00:48:54,530
l zeroes u dawk li jirrappreżentaw il-programm tiegħek.

1099
00:48:54,530 --> 00:48:56,690
Fil-qosor, din hija biss super, bad super.

1100
00:48:56,690 --> 00:48:56,860
Dritt?

1101
00:48:56,860 --> 00:48:58,620
Programm tagħkom telgħu barra mill-kontroll.

1102
00:48:58,620 --> 00:49:02,840
Inti qed tuża memorja mod aktar milli suppost intenzjonat kollha minħabba stupid

1103
00:49:02,840 --> 00:49:03,920
żball, f'dan il-każ.

1104
00:49:03,920 --> 00:49:08,160
Jew f'dan il-każ, funzjoni very deliberatament jsir ssejjaħ lilha nnifisha.

1105
00:49:08,160 --> 00:49:09,210
Issa dan mhux kollox ħażin.

1106
00:49:09,210 --> 00:49:12,540
Funzjonijiet li ssejjaħ infushom attwalment għandha setgħa kbira

1107
00:49:12,540 --> 00:49:13,700
meta tuża b'mod korrett.

1108
00:49:13,700 --> 00:49:15,650
I ma jkunux użati b'mod korrett hawnhekk.

1109
00:49:15,650 --> 00:49:16,940
>> Allura dan mhux kollox ħażin.

1110
00:49:16,940 --> 00:49:20,620
Imma l-fatt li jien qatt ma attwalment niefqu milli nsejħulha myself hija fundamentali

1111
00:49:20,620 --> 00:49:23,050
dgħjufija hawn dan il-programm.

1112
00:49:23,050 --> 00:49:25,090
Għalhekk, fejn huma aħna se kollha ta 'dan?

1113
00:49:25,090 --> 00:49:26,230
Ukoll, dak li verament jiġri?

1114
00:49:26,230 --> 00:49:30,010
Meta I-sejħa l-funzjoni inkrement, bħal aħna kienu qed jagħmlu fil dawn l-eżempji,

1115
00:49:30,010 --> 00:49:33,290
I jkollhom valur bħal 1 li I jgħaddu pulzieri

1116
00:49:33,290 --> 00:49:35,820
I jgħaddu f'kopja tad-numru wieħed.

1117
00:49:35,820 --> 00:49:37,080
Allura li ġej jiġri.

1118
00:49:37,080 --> 00:49:40,390
Mela ejja jmorru fil-eżempju inkrement.

1119
00:49:40,390 --> 00:49:44,230
U dan Guy dritt fuq hawn.

1120
00:49:44,230 --> 00:49:46,800
Allura hawnhekk huwa dak li verament jiġri.

1121
00:49:46,800 --> 00:49:50,770
Meta I imsejħa żieda, u I jgħaddu x-pictorially x'hemm

1122
00:49:50,770 --> 00:49:53,660
għaddejjin hawn hija din -

1123
00:49:53,660 --> 00:50:00,240
jekk Għandi l-valur ta '1 maħżun hawnhekk, u I attwalment sejħa inkrement, li

1124
00:50:00,240 --> 00:50:02,680
li issa hija msejħa kor -

1125
00:50:02,680 --> 00:50:04,010
yeah, li l-jitfg me off hawn.

1126
00:50:04,010 --> 00:50:06,750
Mela ejja sejħa dan inkrement.

1127
00:50:06,750 --> 00:50:09,420
U aħna ma jafux liema din il-funzjoni li jmiss li għaddej biex tkun.

1128
00:50:09,420 --> 00:50:14,270
Allura dak li verament jiġri huwa hawn x'imkien prinċipali, għandi blokki ta '

1129
00:50:14,270 --> 00:50:16,670
memorja li huwa ħażna in-numru 1.

1130
00:50:16,670 --> 00:50:19,730
Meta I call inkrement, jien jużaw ieħor blokki ta 'memorja, imma issa I

1131
00:50:19,730 --> 00:50:20,840
għandhom il-kopja ta '1.

1132
00:50:20,840 --> 00:50:25,480
Meta I inkrement li l-valur, dan isir 2 - horribly bil-miktub dwar il-

1133
00:50:25,480 --> 00:50:26,420
iskrin hawn.

1134
00:50:26,420 --> 00:50:30,550
Iżda mbagħad, dak li jiġri hekk kif prospetti inkrement?

1135
00:50:30,550 --> 00:50:34,610
Din il-memorja biss gets mogħtija lura lill-sistema operattiva, li tfisser kull

1136
00:50:34,610 --> 00:50:37,470
inti ghamilt xejn utli.

1137
00:50:37,470 --> 00:50:43,460
Il-wieħed li kien oriġinarjament jinsabu fil prinċipali għadu attwalment hemm.

1138
00:50:43,460 --> 00:50:44,650
>> Għalhekk, fejn huma aħna għaddejjin ma 'dan?

1139
00:50:44,650 --> 00:50:49,400
Ukoll, jirriżulta li fil-memorja għandek dan lura lura sekwenza ta '

1140
00:50:49,400 --> 00:50:50,940
bytes li inti tista 'tpoġġi Jittieħed pulzieri

1141
00:50:50,940 --> 00:50:53,760
U jirriżulta li aħna stajt diġà raw xi ħaġa li tinvolvi t-tqegħid

1142
00:50:53,760 --> 00:50:55,100
affarijiet lura lura lura lura.

1143
00:50:55,100 --> 00:51:00,170
X'inhu string, ibbażata fuq ġimgħa waħda u issa ġimgħatejn?

1144
00:51:00,170 --> 00:51:01,840
Allura huwa biss ġabra ta 'karattri.

1145
00:51:01,840 --> 00:51:05,290
Għalhekk jirriżulta, hekk kif inti tista 'tpoġġi numri fil-memorja, bl-istess mod inti tista'

1146
00:51:05,290 --> 00:51:06,900
jitqiegħdu karattri fil-memorja.

1147
00:51:06,900 --> 00:51:09,810
U ladarba nibdew karattri tqegħid fil-memorja lura lura lura biex

1148
00:51:09,810 --> 00:51:12,800
lura, jirriżulta li l-użu l-aktar sempliċi ta 'affarijiet bħal għal loop jew

1149
00:51:12,800 --> 00:51:14,510
linja filwaqt li, nistgħu jtenni -

1150
00:51:14,510 --> 00:51:17,130
mix-xellug għal-lemin fuq il-karattri fit string -

1151
00:51:17,130 --> 00:51:20,720
u tibda timmassaġġja minnhom fil-karattri differenti għal kollox.

1152
00:51:20,720 --> 00:51:25,550
A tista 'ssir B. B jista' jsir C. Allura li finalment, nistgħu nieħdu l-

1153
00:51:25,550 --> 00:51:28,830
Sentenza Ingliża li attwalment jagħmel sens u jikkonvertu kull wieħed minn dawk

1154
00:51:28,830 --> 00:51:32,440
ittri wieħed kull darba bil-mixi permezz memorja tal-kompjuter tagħna xellug għal

1155
00:51:32,440 --> 00:51:34,300
dritt li fil-fatt kriptaġġ.

1156
00:51:34,300 --> 00:51:36,590
>> Mela ejja tagħti ħames minuti break tagħna hawn, u meta niġu lura, aħna ser

1157
00:51:36,590 --> 00:51:39,060
bidu dan il-proċess ta scrambling informazzjoni.

1158
00:51:41,640 --> 00:51:43,180
>> Kull dritt.

1159
00:51:43,180 --> 00:51:48,440
Għalhekk qabel we adsa fl għal xi kripto u dawn l-affarijiet imsejħa arrays, let me

1160
00:51:48,440 --> 00:51:51,610
nieqaf għal xi mistoqsijiet għaliex inħoss bħal I really tip ta 'xejn ċar xi

1161
00:51:51,610 --> 00:51:52,230
dawk is-suġġetti.

1162
00:51:52,230 --> 00:51:53,940
Mela ejja tiffissa issa jekk nistgħu.

1163
00:51:53,940 --> 00:51:56,480
Allura aħna biss tkellem dwar il-valuri ta 'ritorn.

1164
00:51:56,480 --> 00:51:58,630
Aħna tkellimna dwar l-argumenti.

1165
00:51:58,630 --> 00:52:02,330
U tkellimna dwar dan il-kunċett, li aħna ser terga 'lura fit-ġimgħat li

1166
00:52:02,330 --> 00:52:07,140
ġejjin, tal-wiri tal-memorja bħala mazz sħiħ ta 'dawn stacked

1167
00:52:07,140 --> 00:52:08,540
trejs, biex ngħidu hekk.

1168
00:52:08,540 --> 00:52:13,460
Minn qiegħ fuq up, b'tali mod li kull trej li gets mqiegħda fis-munzell jirrappreżenta

1169
00:52:13,460 --> 00:52:15,160
funzjoni li l-li bħalissa qed jissejħu.

1170
00:52:17,970 --> 00:52:20,300
Kwalunkwe mistoqsijiet?

1171
00:52:20,300 --> 00:52:22,890
Allura kif madwar - let me tipprova tistaqsi mistoqsija.

1172
00:52:22,890 --> 00:52:25,520
I iżommu spoiling, iżda issa it's - you've kollha raw wiċċ tal-boy.

1173
00:52:25,520 --> 00:52:27,020
Allura aħna ser terga 'lura għal dan.

1174
00:52:27,020 --> 00:52:29,700
>> So let me jistaqsu mistoqsija hawn.

1175
00:52:29,700 --> 00:52:34,810
Let me jissimplifikaw dan lura għal dak li kien qabel xi wħud Q preċedenti tagħna & A.

1176
00:52:34,810 --> 00:52:41,730
U l-fatt li żieda għandha parentesi miftuħa, in-numru int, magħluqa

1177
00:52:41,730 --> 00:52:42,260
parentesi.

1178
00:52:42,260 --> 00:52:46,370
Xi jfisser in-numru int jirrappreżenta?

1179
00:52:46,370 --> 00:52:47,250
[Inaudible]

1180
00:52:47,250 --> 00:52:47,870
DAVID J. Malan: An argument.

1181
00:52:47,870 --> 00:52:50,732
Okay, imma dak argument?

1182
00:52:50,732 --> 00:52:51,620
[Inaudible]

1183
00:52:51,620 --> 00:52:52,500
DAVID J. Malan: Jiddispjacini, dak li?

1184
00:52:52,500 --> 00:52:53,150
SPEAKER 3: Haga inti tgħaddi pulzieri

1185
00:52:53,150 --> 00:52:53,570
DAVID J. Malan: Okay.

1186
00:52:53,570 --> 00:52:54,780
Allura xi ħaġa li inti tgħaddi pulzieri

1187
00:52:54,780 --> 00:52:56,560
U b'mod aktar ġenerali, huwa biss l-input.

1188
00:52:56,560 --> 00:52:59,860
Jekk int bil-miktub funzjoni u l-iskop li l-funzjoni fil-ħajja huwa li tagħmel

1189
00:52:59,860 --> 00:53:03,290
xi ftit differenti kull darba li tużah, allura l-uniku mod għal

1190
00:53:03,290 --> 00:53:07,710
dak li jiġri verament jidher li jkun li jipprovdilha kontribut sabiex

1191
00:53:07,710 --> 00:53:10,180
tista 'tagħmel xi ħaġa differenti ma' dak l-input kull darba.

1192
00:53:10,180 --> 00:53:13,590
>> Għalhekk ikollok bżonn li jispeċifikaw żewġ affarijiet meta l-funzjoni jieħu inputs.

1193
00:53:13,590 --> 00:53:17,240
Ikollok bżonn li jispeċifikaw l-isem li inti tixtieq li tagħti għal dik input, purament għall

1194
00:53:17,240 --> 00:53:20,790
konvenjenza tiegħek sabiex inti tista 'tirreferi lilu fejn għandu l-funzjoni li inti

1195
00:53:20,790 --> 00:53:23,610
yourself qed tikteb, kif għamilt hawn fil-linja 32.

1196
00:53:23,610 --> 00:53:27,840
Imma inti wkoll bżonn biex jispeċifika t-tip tagħha għaliex Ċ hija lingwa ta 'programmar

1197
00:53:27,840 --> 00:53:28,840
li biss jeħtieġ

1198
00:53:28,840 --> 00:53:31,810
li jekk inti tixtieq varjabbli, inti għandek tgħid il-kompjuter liema

1199
00:53:31,810 --> 00:53:32,790
data tip huwa,

1200
00:53:32,790 --> 00:53:35,540
fil-parti kbira hekk li jaf kemm bits għal

1201
00:53:35,540 --> 00:53:37,230
jalloka għal dan il-varjabbli.

1202
00:53:37,230 --> 00:53:38,600
Minħabba li jista 'jkun 6 -

1203
00:53:38,600 --> 00:53:39,990
sorry, dan mhux se jkun 6.

1204
00:53:39,990 --> 00:53:41,050
Jista 'jkun 16.

1205
00:53:41,050 --> 00:53:41,630
Hija tista 'tkun 8.

1206
00:53:41,630 --> 00:53:44,410
Hija tista 'tkun 32, anke 64.

1207
00:53:44,410 --> 00:53:45,820
Iżda l-kompjuter jeħtieġ li tkun taf.

1208
00:53:45,820 --> 00:53:49,110
Issa l-int fuq in-naħa tax-xellug jirrappreżenta dak, b'kuntrast?

1209
00:53:52,825 --> 00:53:53,780
[Inaudible]

1210
00:53:53,780 --> 00:53:54,570
DAVID J. Malan: X'hemm li?

1211
00:53:54,570 --> 00:53:55,390
[Inaudible]

1212
00:53:55,390 --> 00:53:57,920
DAVID J. Malan: It-tip tal-funzjoni u, b'mod aktar speċifiku, il-

1213
00:53:57,920 --> 00:53:59,755
tip ta 'produzzjoni tagħha.

1214
00:53:59,755 --> 00:54:00,220
Dritt.

1215
00:54:00,220 --> 00:54:04,220
Allura filwaqt li l-ħaġa fil-parentesi jirrappreżenta input tagħha, jekk ikun hemm, il-

1216
00:54:04,220 --> 00:54:06,640
Ħaġa lejn ix-xellug jirrappreżenta produzzjoni tagħha.

1217
00:54:06,640 --> 00:54:10,560
U f'dan il-każ, iż-żieda apparentement jirritorna int.

1218
00:54:10,560 --> 00:54:14,590
U għalhekk int huwa t-tip ritorn ta 'din il-funzjoni.

1219
00:54:14,590 --> 00:54:16,090
>> Xi jfisser li jirritornaw?

1220
00:54:16,090 --> 00:54:19,810
Litteralment, tuża r-ritorn keyword.

1221
00:54:19,810 --> 00:54:24,640
U mbagħad jekk dak li qed jirritornaw lejn il-lemin tal-keyword huwa

1222
00:54:24,640 --> 00:54:28,340
numru sħiħ, allura dan hu tassew konsistenti ma 'dak li għandna imwiegħed.

1223
00:54:28,340 --> 00:54:31,110
Inti ma setgħux jagħmlu xi ħaġa bħal din -

1224
00:54:31,110 --> 00:54:32,280
hello, dinja -

1225
00:54:32,280 --> 00:54:33,500
għaliex dik hija string.

1226
00:54:33,500 --> 00:54:35,440
Ovvjament mhuwiex numru sħiħ.

1227
00:54:35,440 --> 00:54:40,450
Allura fil-qosor, il-piż huwa verament fuqna, il-programmer, li tkun speċifika kemm

1228
00:54:40,450 --> 00:54:44,730
għal dak li aħna qed jirritornaw u li mbagħad fil-fatt imorru dwar jirritornaha.

1229
00:54:44,730 --> 00:54:49,030
U mbagħad tagħmel tad aktar ċara tal-kuntest -

1230
00:54:49,030 --> 00:54:50,080
hemm hu ġdid.

1231
00:54:50,080 --> 00:54:51,060
Il-kuntest -

1232
00:54:51,060 --> 00:54:52,830
sorpriża kbira li ġejjin fil ftit mument.

1233
00:54:52,830 --> 00:54:57,720
Il-kuntest hawn issa huwa li l-memorja tal-kompjuter tiegħek huwa, għal darb'oħra,

1234
00:54:57,720 --> 00:54:59,070
gigabyte, żewġ gigabytes, tkun xi tkun.

1235
00:54:59,070 --> 00:54:59,630
Forsi huwa aktar.

1236
00:54:59,630 --> 00:55:00,540
Forsi huwa inqas.

1237
00:55:00,540 --> 00:55:03,750
Iżda l-kompjuter fehmiet bħala li għandhom taqsimiet differenti.

1238
00:55:03,750 --> 00:55:04,860
Xi ħaġa tmur stabbiliti hemmhekk.

1239
00:55:04,860 --> 00:55:06,020
Xi ħaġa oħra tmur up hemm.

1240
00:55:06,020 --> 00:55:07,540
Jittieħed differenti tmur fin-nofs.

1241
00:55:07,540 --> 00:55:09,300
U llum, aħna biss tibda javżak din l-istorja.

1242
00:55:09,300 --> 00:55:11,130
>> Iżda aħna ser terġa 'lura għal dan iż-żmien fuq.

1243
00:55:11,130 --> 00:55:15,000
Għal issa, il-biċċa biss ta 'memorja aħna verament jimpurtak huwa l-segment test

1244
00:55:15,000 --> 00:55:17,160
minħabba li ftit tirrappreżenta l zeroes u dawk

1245
00:55:17,160 --> 00:55:18,460
li clang tkun outputted.

1246
00:55:18,460 --> 00:55:21,570
Allura meta inti tmexxi kmand fil-keyboard simili a.out, jew inti doppja

1247
00:55:21,570 --> 00:55:25,350
ikklikkja l-ikona fuq Mac OS jew Windows, programm tiegħek mgħobbija minn drive tiegħek

1248
00:55:25,350 --> 00:55:26,930
issuq fil-RAM.

1249
00:55:26,930 --> 00:55:30,850
U huwa plopped fil-quċċata ta 'RAM kompjuter tiegħek, biex ngħidu hekk.

1250
00:55:30,850 --> 00:55:35,470
Issa sadanittant, kif program tiegħek tibda taħdem u ewlieni gets msejħa fl-

1251
00:55:35,470 --> 00:55:39,240
programm inti kiteb jew il-Microsoft programm jew Apple kiteb, xi tagħha

1252
00:55:39,240 --> 00:55:42,930
varjazzjonijiet lokali jispiċċaw stabbiliti hemmhekk fil-qiegħ tal-memorja tal-kompjuter tiegħek.

1253
00:55:42,930 --> 00:55:46,490
Iżda jekk jitlob prinċipali funzjoni oħra li hi stess tkun varjabbli jew

1254
00:55:46,490 --> 00:55:48,340
argumenti, huma jispiċċaw hawn fuq.

1255
00:55:48,340 --> 00:55:50,670
U jekk dik il-funzjoni sejħiet xi ħaġa, huma jispiċċaw hawn fuq,

1256
00:55:50,670 --> 00:55:51,840
hawn fuq, hawn fuq.

1257
00:55:51,840 --> 00:55:56,100
U darba biss funzjoni isir esekuzzjoni ma l-munzell ta 'dixxijiet, għalhekk

1258
00:55:56,100 --> 00:55:58,320
biex jitkellmu, tibda tikseb iktar baxxi.

1259
00:55:58,320 --> 00:56:03,370
U dan huwa dak li mbagħad, fi ftit kliem, tispjega għaliex, meta inti sejħa kubu -

1260
00:56:03,370 --> 00:56:04,660
jew inti sejħa inkrement -

1261
00:56:04,660 --> 00:56:06,490
int tgħaddi f'kopja tal-valur.

1262
00:56:06,490 --> 00:56:09,840
U dak li jfisser pictorially hija li int litteralment bil-miktub l-

1263
00:56:09,840 --> 00:56:14,540
numru 1 f'parti oħra ta 'memorja, li jinbidlu li 1 sa 2, fil-każ ta'

1264
00:56:14,540 --> 00:56:15,360
inkrement -

1265
00:56:15,360 --> 00:56:17,450
jew lil 8, fil-każ ta 'kubu -

1266
00:56:17,450 --> 00:56:21,450
u mbagħad jitfg li l-memorja bogħod hekk kif il-inkrement jew il-kubu

1267
00:56:21,450 --> 00:56:23,410
funzjoni prospetti.

1268
00:56:23,410 --> 00:56:24,267
>> Mistoqsija.

1269
00:56:24,267 --> 00:56:25,517
[Inaudible]

1270
00:56:28,090 --> 00:56:29,970
DAVID J. Malan: Fejn - varjabbli globali huma maħżuna fil x'hemm

1271
00:56:29,970 --> 00:56:32,960
bħalissa msejjaħ id-data initialized jew data uninitialized.

1272
00:56:32,960 --> 00:56:35,900
Id-differenza hija, jekk għandek varjabbli globali, u inti tassenja din

1273
00:56:35,900 --> 00:56:39,530
immedjatament valur ugwali ma 'l-sinjal, dan jispiċċa fil-quċċata hemmhekk.

1274
00:56:39,530 --> 00:56:43,390
U jekk inti biss jgħidu int x virgola bl-ebda valur, dan jispiċċa ftit

1275
00:56:43,390 --> 00:56:46,670
aktar baxx fl-RAM sempliċiment billi konvenzjoni.

1276
00:56:46,670 --> 00:56:49,308
Mistoqsijiet oħra.

1277
00:56:49,308 --> 00:56:49,750
Kull dritt.

1278
00:56:49,750 --> 00:56:53,040
>> Allura din l-istampa se terga 'lura kif aħna nikseb aktar qawwija ma' dak li nistgħu nagħmlu

1279
00:56:53,040 --> 00:56:53,830
mal-kompjuter.

1280
00:56:53,830 --> 00:56:58,790
Iżda għal issa, ejja jkollhom intro qasira għall-kriptografija, tip speċifiku ta '

1281
00:56:58,790 --> 00:57:01,910
kriptografija li ma isolvi l-problemi tad-dinja, iżda ma ssolvi

1282
00:57:01,910 --> 00:57:02,480
xi wħud minnhom.

1283
00:57:02,480 --> 00:57:06,090
F'dan il-każ hawnhekk, aħna għandna xi ħaġa imsejħa kriptografija ċavetta sigriet.

1284
00:57:06,090 --> 00:57:10,430
U kriptografija sigrieti ewlenin, kif tissuġġerixxi l-isem, joħroġ sigurtà tagħha

1285
00:57:10,430 --> 00:57:11,330
minn sigriet.

1286
00:57:11,330 --> 00:57:14,720
Għalhekk per eżempju, jekk int lura fl-iskola grad u int tgħaddi minn

1287
00:57:14,720 --> 00:57:18,040
ftit sigriet imħabba ittra lill-tifel jew tifla li qed tgħaffiġ fuq - jekk inti

1288
00:57:18,040 --> 00:57:20,820
riedu li jgħaddu li permezz tal-udjenza, inti probabilment mhux se jikteb

1289
00:57:20,820 --> 00:57:24,120
tali nota bl-Ingliż jew kwalunkwe lingwa tiegħek huwa, iżda, inti

1290
00:57:24,120 --> 00:57:25,800
jista 'kriptaġġ.

1291
00:57:25,800 --> 00:57:27,820
Jew inti tista 'biss tibgħathom messaġġ f'dawn il-jiem.

1292
00:57:27,820 --> 00:57:30,310
Iżda int tista 'attwalment jgħaddihom nota matul il-klassi.

1293
00:57:30,310 --> 00:57:33,820
U biex tagħmel dan b'mod sikur, b'tali mod li l-ħbieb tiegħek u l-għalliema

1294
00:57:33,820 --> 00:57:36,820
ma nafx dak li qed tikteb, inti tista 'toħroġ bi pjuttost sempliċi

1295
00:57:36,820 --> 00:57:37,800
algoritmu -

1296
00:57:37,800 --> 00:57:39,290
żgħażagħ għalkemm inti tista 'tkun -

1297
00:57:39,290 --> 00:57:40,780
biss ġirja-kliem.

1298
00:57:40,780 --> 00:57:44,390
Allura minflok bil-miktub A, inti tista 'tikteb B. Minflok B, inti tista' tikteb

1299
00:57:44,390 --> 00:57:46,670
C. Minflok C, inti tista 'tikteb D, u ibqa' sejjer hekk.

1300
00:57:46,670 --> 00:57:50,020
Jew inti tista 'toħroġ bi traduzzjoni aktar sofistikati ta' ittri

1301
00:57:50,020 --> 00:57:51,300
għall-ittri differenti.

1302
00:57:51,300 --> 00:57:55,440
Iżda l-qabda hija l-tifel jew tifla li lilha qed tibgħat din in-nota trid

1303
00:57:55,440 --> 00:57:56,850
taf xi ħaġa.

1304
00:57:56,850 --> 00:57:59,620
Liema huwa dak li, ovvjament?

1305
00:57:59,620 --> 00:58:01,400
Bħal, liema sigrieta tiegħek.

1306
00:58:01,400 --> 00:58:04,620
Bħal, dak li huwa li l-immappjar bejn Kif u Bs u Cs u Ds?

1307
00:58:04,620 --> 00:58:08,780
Huwa sempliċement tiżdied wieħed, biex ngħidu hekk, għal kull wieħed mill-ittri li jmorru minn

1308
00:58:08,780 --> 00:58:09,730
A sa B, B sa C?

1309
00:58:09,730 --> 00:58:11,350
Huwa aktar kumplessa minn dik?

1310
00:58:11,350 --> 00:58:16,450
Allura inti u tgħaffiġ tiegħek jeħtieġ li jkollhom din l-informazzjoni sigrieta.

1311
00:58:16,450 --> 00:58:18,170
Iżda hemm tip ta 'qabda-22 here.

1312
00:58:18,170 --> 00:58:20,760
Jekk dan huwa l-ewwel darba li qed tibgħat din l-ittra imħabba permezz tal-

1313
00:58:20,760 --> 00:58:25,590
klassi, kif huwa li tifel jew tifla se tkun taf liema l-sigrieti anke hu?

1314
00:58:25,590 --> 00:58:28,450
Allura sigriet ewlieni kripto ma ssolvix il-problemi kollha tad-dinja.

1315
00:58:28,450 --> 00:58:30,490
U hemm attwalment relazzjoni li aħna ser terga 'lura għal lejn

1316
00:58:30,490 --> 00:58:31,370
aħħar semestru tal-.

1317
00:58:31,370 --> 00:58:35,970
>> Bl-istess mod, m'għandhom xejn minna probabbilment qatt bagħtet -

1318
00:58:35,970 --> 00:58:39,453
bl-istess mod, do ħafna minna ma jafux xi ħadd li jaħdem, per eżempju, fil-

1319
00:58:39,453 --> 00:58:40,300
Amazon.com.

1320
00:58:40,300 --> 00:58:43,130
And yet, ħafna minna probabbilment mixtrija Jittieħed fuq Amazon.com.

1321
00:58:43,130 --> 00:58:45,670
U aħna kont qed mgħallma li wieħed jassumi li dawn le-commerce

1322
00:58:45,670 --> 00:58:47,060
transazzjonijiet huma sikuri.

1323
00:58:47,060 --> 00:58:47,210
Dritt?

1324
00:58:47,210 --> 00:58:49,310
Il-URL probabbilment jgħid https.

1325
00:58:49,310 --> 00:58:51,590
Hemm forsi ikona katnazz iblah ftit x'imkien.

1326
00:58:51,590 --> 00:58:54,680
Hemm xi tip ta 'kriptografija żgurati l-informazzjoni tiegħek karta ta' kreditu

1327
00:58:54,680 --> 00:58:56,980
bejnek u Amazon.com.

1328
00:58:56,980 --> 00:59:00,410
And yet, jekk kriptografija jinvolvi jafu xi sigriet, u għadhom I ma

1329
00:59:00,410 --> 00:59:03,330
taf xi ħadd fil-Amazon, u stajt ċertament mhux irranġati xi tip ta '

1330
00:59:03,330 --> 00:59:07,350
sigriet ma 'xi ħadd fil-Amazon, kif huwa kompjuter tiegħi jew browser tiegħi tagħmel dan?

1331
00:59:07,350 --> 00:59:10,100
Ukoll, jirriżulta hemm tipi oħra ta 'kriptografija għal kollox li ssolvi

1332
00:59:10,100 --> 00:59:10,740
dik il-problema.

1333
00:59:10,740 --> 00:59:13,610
Iżda għal-lum, aħna ser tiffoka fuq il-wieħed sempliċi, fejn inti tista 'tirranġa fil

1334
00:59:13,610 --> 00:59:18,480
javvanzaw tkun taf xi sigriet, bħal plus 1 jew xi immappjar bejn Kif u Bs.

1335
00:59:18,480 --> 00:59:20,710
>> U l-proċess ta 'kriptografija ġeneralment jinvolvi dan.

1336
00:59:20,710 --> 00:59:23,550
Inti għandek xi test sempliċi, jidhru hawn fuq xellug.

1337
00:59:23,550 --> 00:59:26,260
You run permezz ta 'xi tip ta' algoritmu jew il-proċedura

1338
00:59:26,260 --> 00:59:27,670
għall encrypting dan.

1339
00:59:27,670 --> 00:59:31,390
Forsi dan huwa biss A issir B, B isir C. U allura inti tispiċċa bil

1340
00:59:31,390 --> 00:59:32,260
cipher test.

1341
00:59:32,260 --> 00:59:36,450
Sadanittant, ladarba tgħaffiġ tiegħek tirċievi n-nota sigriet, hu jew hi għandu mbagħad

1342
00:59:36,450 --> 00:59:39,950
decrypt dan billi ġeneralment rivers li algoritmu sabiex tikseb

1343
00:59:39,950 --> 00:59:41,640
lura t-test sempliċi.

1344
00:59:41,640 --> 00:59:43,860
Issa hemm incarnations fiżiċi ta 'dan.

1345
00:59:43,860 --> 00:59:46,720
Per eżempju, dan huwa ċirku ftit decoder sigriet.

1346
00:59:46,720 --> 00:59:50,060
U dan huwa ċirku fis-sens li hemm żewġ dials hawn.

1347
00:59:50,060 --> 00:59:53,630
Fuq il-periferija ta 'barra tal dan il-ħaġa, hemm l-ittri a sa Z,

1348
00:59:53,630 --> 00:59:55,110
għalkemm dawn qed sabiex każwali.

1349
00:59:55,110 --> 00:59:58,410
U fuq il-ġewwa, hemm attwalment xi numri, tali li ma 'dan

1350
00:59:58,410 --> 01:00:02,940
ċirku, inti tista 'tip ta' ddawar il-barra imma mhux ġewwa sabiex linja up

1351
01:00:02,940 --> 01:00:04,110
numri ma 'ittri.

1352
01:00:04,110 --> 01:00:08,290
U fil-clip int ser tara - li wħud minnhom inti tista raw 24/7

1353
01:00:08,290 --> 01:00:11,120
madwar l-istaġun tal-Milied minn movie imsejjaħ A Story Milied.

1354
01:00:11,120 --> 01:00:16,050
Int ser ikollok tara li Ralphie ftit kien tant ħerqana biex insemmu dak orfni ftit

1355
01:00:16,050 --> 01:00:19,810
Messaġġ sigriet Annie kien lilu li kienu ġew ikkomunikati, naħseb, fl-

1356
01:00:19,810 --> 01:00:22,810
forma ta 'messaġġi numeriċi fuq kaxxa tas-serje.

1357
01:00:22,810 --> 01:00:26,760
U kellek biex jakkumulaw l-karti ftit li daħal

1358
01:00:26,760 --> 01:00:27,480
fil-kaxxa ċereali.

1359
01:00:27,480 --> 01:00:28,320
Kellek għall-posta lilhom pulzieri

1360
01:00:28,320 --> 01:00:31,060
Inti kellha terġa 'lura l-ċirku decoder sigriet, sabiex inti tista' finalment figura

1361
01:00:31,060 --> 01:00:34,190
barra dak l-immappjar huwa bejn l-ittri u numri,

1362
01:00:34,190 --> 01:00:35,420
jew ittri u ittri.

1363
01:00:35,420 --> 01:00:39,790
So I jagħtuk din clip qasir minn A Story Milied biex jimmotivaw pset 2 u

1364
01:00:39,790 --> 01:00:42,340
diskussjoni tagħna, fil-mument, ta 'arrays.

1365
01:00:42,340 --> 01:00:43,773
Allura hawnhekk għandna Ralphie.

1366
01:00:43,773 --> 01:00:44,126
>> [Daqq ta 'video]

1367
01:00:44,126 --> 01:00:47,470
-Be hija magħrufa għal kulħadd u varji li Ralph Parker huwa b'dan maħtur

1368
01:00:47,470 --> 01:00:50,690
membru tal-Ċirku Orfni Little Secret Annie u huwa intitolat għal kulħadd

1369
01:00:50,690 --> 01:00:53,500
l-unuri u l-benefiċċji li jseħħu magħhom.

1370
01:00:53,500 --> 01:00:56,040
Iffirmat-, Orphan Annie Little.

1371
01:00:56,040 --> 01:00:58,730
Kontrofirmata, Pierre Andre!

1372
01:00:58,730 --> 01:01:00,150
Fil linka!

1373
01:01:00,150 --> 01:01:02,910
Honors u l-benefiċċji, li diġà fl-età ta 'disa'.

1374
01:01:09,970 --> 01:01:10,730
Come on, ejja nikseb fuq magħha.

1375
01:01:10,730 --> 01:01:15,000
I m'għandhomx bżonn dak kollu li jazz dwar kuntrabandisti u l-pirati.

1376
01:01:15,000 --> 01:01:17,624
Isma 'bil-lejl ta' għada għall-avventura konklużjoni ta 'The Black

1377
01:01:17,624 --> 01:01:19,710
Vapur pirata.

1378
01:01:19,710 --> 01:01:23,380
Issa wasal iż-żmien għall-messaġġ sigriet Annie s għalik membri

1379
01:01:23,380 --> 01:01:25,670
tal-Ċirku Sigriet.

1380
01:01:25,670 --> 01:01:30,260
Ftakar, gidjien, membri tal Circle Secret Annie jista 'jiddekowdja

1381
01:01:30,260 --> 01:01:31,660
Messaġġ sigriet Annie s.

1382
01:01:31,660 --> 01:01:36,230
Ftakar, Annie jiddependi fuq int.

1383
01:01:36,230 --> 01:01:38,720
Set labar tiegħek lil B2.

1384
01:01:38,720 --> 01:01:41,040
Hawn hu l-messaġġ.

1385
01:01:41,040 --> 01:01:42,470
12, 11 -

1386
01:01:42,470 --> 01:01:46,000
-I am fil-laqgħa tiegħi sigrieta 1.

1387
01:01:46,000 --> 01:01:49,440
-14, 11, 18, 16 -

1388
01:01:49,440 --> 01:01:51,700
-Pierre kien tonight vuċi kbira.

1389
01:01:51,700 --> 01:01:54,890
I tista 'tgħid li l-messaġġ tonight kien verament importanti.

1390
01:01:54,890 --> 01:01:56,750
-3, 25.

1391
01:01:56,750 --> 01:01:58,590
Li l-messaġġ mill Annie ruħha.

1392
01:01:58,590 --> 01:01:59,840
Ftakar, ma tgħid xi ħadd.

1393
01:02:04,570 --> 01:02:08,750
-90 Sekondi wara, jien fil-kamra biss fid-dar fejn tifel ta 'disa'

1394
01:02:08,750 --> 01:02:12,980
jistgħu ipoġġu fil-privatezza u jiddekowdja.

1395
01:02:12,980 --> 01:02:17,130
Ah, B. I marru għall-ieħor.

1396
01:02:17,130 --> 01:02:20,330
E. L-ewwel kelma hija tkun.

1397
01:02:20,330 --> 01:02:22,670
S. Hija kien ġejjin faċli issa.

1398
01:02:22,670 --> 01:02:24,590
U.

1399
01:02:24,590 --> 01:02:26,510
Oh, come fuq, Ralphie.

1400
01:02:26,510 --> 01:02:28,430
Sibt li jmorru.

1401
01:02:28,430 --> 01:02:30,350
I'll jiġu-dritt isfel, ma.

1402
01:02:30,350 --> 01:02:33,720
-GEE whiz.

1403
01:02:33,720 --> 01:02:38,270
-T, O. Kun żgur li.

1404
01:02:38,270 --> 01:02:40,000
Kun żgur li dak li?

1405
01:02:40,000 --> 01:02:42,105
Liema kienet Little Orfni Annie nipprova ngħid?

1406
01:02:42,105 --> 01:02:43,095
Kun żgur li dak li?

1407
01:02:43,095 --> 01:02:43,590
-Ralphie!

1408
01:02:43,590 --> 01:02:44,580
Randy s'est li jmorru.

1409
01:02:44,580 --> 01:02:45,570
Gaat jekk jogħġbok toħroġ?

1410
01:02:45,570 --> 01:02:46,560
-Id-dritt, ma.

1411
01:02:46,560 --> 01:02:48,540
I ser tkun dritt out.

1412
01:02:48,540 --> 01:02:50,580
-I kien jkollna aktar mill-qrib issa.

1413
01:02:50,580 --> 01:02:52,550
It-tensjoni kienet diżappuntanti.

1414
01:02:52,550 --> 01:02:53,355
Liema kien dan?

1415
01:02:53,355 --> 01:02:56,315
Il-destin tal-pjaneta jista hang fil-bilanċ.

1416
01:02:56,315 --> 01:02:56,790
-Ralphie!

1417
01:02:56,790 --> 01:02:59,165
Randy ltqajna biex imorru.

1418
01:02:59,165 --> 01:03:02,310
-I'll tkun id-dritt, għal biki out loud.

1419
01:03:02,310 --> 01:03:04,000
-GEE, kważi hemm.

1420
01:03:04,000 --> 01:03:05,180
Swaba tiegħi taru.

1421
01:03:05,180 --> 01:03:07,150
Moħħ tiegħi kien nassa azzar.

1422
01:03:07,150 --> 01:03:08,790
Kull pori ivvibrat.

1423
01:03:08,790 --> 01:03:10,040
Kien kważi ċara.

1424
01:03:10,040 --> 01:03:13,400
Iva, iva, iva, iva.

1425
01:03:13,400 --> 01:03:18,960
-Kun żgur li tixrob Ovaltine tiegħek.

1426
01:03:18,960 --> 01:03:20,210
Ovaltine?

1427
01:03:24,010 --> 01:03:25,260
A crummy kummerċjali?

1428
01:03:28,200 --> 01:03:29,640
Iben ta 'kelba.

1429
01:03:29,640 --> 01:03:33,340
[END video daqq]

1430
01:03:33,340 --> 01:03:36,040
>> DAVID J. Malan: Allura hemm aħna għandna kriptografija.

1431
01:03:36,040 --> 01:03:39,670
Allura kif fil-kompjuter nistgħu tmur dwar implimentazzjoni jew

1432
01:03:39,670 --> 01:03:40,950
jirrappreżentaw affarijiet bħal dan?

1433
01:03:40,950 --> 01:03:44,430
Ukoll, għandna bżonn mod li jesprimu nfusna ftit aktar flessibbli minn

1434
01:03:44,430 --> 01:03:46,420
Varjabbli tagħna s'issa ippermettew.

1435
01:03:46,420 --> 01:03:47,370
Aħna kellna ints.

1436
01:03:47,370 --> 01:03:48,380
Aħna kellna Chars.

1437
01:03:48,380 --> 01:03:50,790
Aħna kellna flowts u jirdoppja u fi ftit oħrajn.

1438
01:03:50,790 --> 01:03:55,050
Iżda dawn huma biċċiet individwali ta 'memorja li ma verament jippermettu magħna biex

1439
01:03:55,050 --> 01:03:58,010
jesprimu affarijiet simili kliem u sentenzi u frażijiet.

1440
01:03:58,010 --> 01:04:00,200
Tabilħaqq, konna imsejħa kordi bħal dawn l-affarijiet.

1441
01:04:00,200 --> 01:04:03,650
Iżda aħna wiegħed li din hija verament ftit simplifikazzjoni fil-CS50

1442
01:04:03,650 --> 01:04:07,020
librerija li aħna qed l-intenzjoni li qoxra lura.

1443
01:04:07,020 --> 01:04:08,970
>> U hekk ejja nibdew biex tagħmel dan hawn.

1444
01:04:08,970 --> 01:04:11,130
Let me imorru quddiem u tiftaħ fajl -

1445
01:04:11,130 --> 01:04:13,770
kollha ta 'dawn il-fajls huma disponibbli bħala online soltu -

1446
01:04:13,770 --> 01:04:19,120
imsejħa array.c biex isolvu problema mhux relatat mal kordi iżda li żebgħa

1447
01:04:19,120 --> 01:04:23,040
stampa hawn 'kif nistgħu jużaw xi ħaġa imsejħa firxa.

1448
01:04:23,040 --> 01:04:25,530
Firxa hija tip tad-data.

1449
01:04:25,530 --> 01:04:31,320
Huwa tip ta 'varjabbli, ta' tip, li għandha ħafna tipi ta 'data iżgħar

1450
01:04:31,320 --> 01:04:34,150
ġewwa ta 'dan lura lura lura lura.

1451
01:04:34,150 --> 01:04:37,700
Għalhekk per eżempju, jekk irridu li jikteb programm ftit li jagħtik tiegħek

1452
01:04:37,700 --> 01:04:42,110
kwizz medja għal kors bħal 50 li għandha żewġ kwizzijiet, inti tista 'faċilment

1453
01:04:42,110 --> 01:04:45,170
tikteb dan il-programm - ibbażati anke fuq xi wħud mill-materjal il-ġimgħa li għaddiet -

1454
01:04:45,170 --> 01:04:47,770
bl-użu GetInt u l-koppja ta 'varjabbli.

1455
01:04:47,770 --> 01:04:51,920
Int quiz1, int quiz2, u huwa pjuttost sempliċi.

1456
01:04:51,920 --> 01:04:55,930
Huwa forsi 10, 20 linji ta 'kodiċi, mass, biex jimplimentaw programm li jitlob lill-

1457
01:04:55,930 --> 01:05:01,170
utent għall-punteġġi kwizz 2 u mbagħad tikkalkula medja tagħhom billi jżidu magħhom

1458
01:05:01,170 --> 01:05:03,850
flimkien, diviż bi tnejn, u mbagħad istampar tar-riżultati.

1459
01:05:03,850 --> 01:05:06,380
Nistgħu probabbilment jagħmlu dan pretty faċilment issa wara

1460
01:05:06,380 --> 01:05:07,510
xi numru ta 'minuti.

1461
01:05:07,510 --> 01:05:11,005
>> Iżda l-problema hija li jissoponi li 50 kellhom 3 kwizzijiet jew erba '.

1462
01:05:11,005 --> 01:05:13,510
Ejja ngħidu li int riedu li tuża l-istess programm għal klassi li kien

1463
01:05:13,510 --> 01:05:14,850
kull ġimgħa kwizzijiet.

1464
01:05:14,850 --> 01:05:16,610
Aħseb dwar klassi li tkun ġimgħa kwiżż.

1465
01:05:16,610 --> 01:05:20,610
Jekk hemm simili 16 jew hekk ġimgħat semestru, issa għandek 16-varjabbli -

1466
01:05:20,610 --> 01:05:24,270
int quiz1, int quiz2, int quiz3, int quiz4.

1467
01:05:24,270 --> 01:05:27,560
Hekk kif inti tibda tara dan redundancy, dan l-ikkupjar u pasta

1468
01:05:27,560 --> 01:05:31,390
tal-kodiċi, hija għandha tibda tagħmel inti tixtieq kien hemm mod aħjar.

1469
01:05:31,390 --> 01:05:33,930
U Thankfully, minħabba arrays, hemm.

1470
01:05:33,930 --> 01:05:34,980
Mela ejja jagħmlu dan.

1471
01:05:34,980 --> 01:05:38,430
Ewwel, let me jintroduċu ħaġa sempliċi ħafna li konna mhux użati s'issa,

1472
01:05:38,430 --> 01:05:40,140
iżda inti ser tara li kultant fil-kodiċi.

1473
01:05:40,140 --> 01:05:42,360
Dan huwa dak li ġeneralment jissejjaħ kostanti.

1474
01:05:42,360 --> 01:05:45,790
Allura huwa kostanti fis-sens li dan il-valur qatt bidliet.

1475
01:05:45,790 --> 01:05:49,210
Il-konvenzjoni tal-bniedem meta jinħoloq kostanti huwa l-użu l-kapital

1476
01:05:49,210 --> 01:05:51,940
ittri, biss hekk li verament jispikka fil-kodiċi tiegħek.

1477
01:05:51,940 --> 01:05:55,960
U l-keyword speċjali li tuża fit C huwa # tiddefinixxi.

1478
01:05:55,960 --> 01:06:00,250
Mela jekk inti tgħidli # tiddefinixxi, imbagħad spazju, allura l-kelma li inti tixtieq li tuża għal

1479
01:06:00,250 --> 01:06:03,260
Isem il-kostanti, u allura l-valur tal-kostanti.

1480
01:06:03,260 --> 01:06:06,180
Allura l-avviż, din hija differenti minn tassenja xi ħaġa għal varjabbli.

1481
01:06:06,180 --> 01:06:07,020
M'hemm l-ebda ugwali sinjal.

1482
01:06:07,020 --> 01:06:08,240
M'hemm l-ebda virgola.

1483
01:06:08,240 --> 01:06:11,410
Dan huwa dak li ġeneralment magħrufa bħala direttiva preprocessor, iżda aktar fuq

1484
01:06:11,410 --> 01:06:12,210
dak ieħor ħin.

1485
01:06:12,210 --> 01:06:18,540
>> Għal issa, dan joħloq valur ma jinbidlux imsejħa kwizzijiet attwali li

1486
01:06:18,540 --> 01:06:19,940
Valur numeriku huwa 2.

1487
01:06:19,940 --> 01:06:24,020
Allura kullimkien inti tara kwizzijiet, kwizzijiet, kwizzijiet matul dan il-fajl, li l-

1488
01:06:24,020 --> 01:06:25,410
biss in-numru 2.

1489
01:06:25,410 --> 01:06:28,100
Issa, jekk I ħarsa lejn ewlenija issa, ejja ara kif taħdem din.

1490
01:06:28,100 --> 01:06:29,500
Għall-ewwel, jidher ftit cryptic.

1491
01:06:29,500 --> 01:06:31,340
Imma dan kollu Jittieħed minn ġimgħa waħda.

1492
01:06:31,340 --> 01:06:32,710
Staqsi lill-utent għall-gradi.

1493
01:06:32,710 --> 01:06:33,630
Kif nistgħu nagħmlu dan?

1494
01:06:33,630 --> 01:06:35,470
Ukoll, f'konformità 22 -

1495
01:06:35,470 --> 01:06:37,210
dan huwa verament il-parti mmerraq -

1496
01:06:37,210 --> 01:06:40,960
Niddikjara float, iżda mhux biss float wieħed.

1497
01:06:40,960 --> 01:06:44,620
Jien tiddikjara, pjuttost, firxa ta 'valuri b'punt li jvarja.

1498
01:06:44,620 --> 01:06:49,100
Dan il-varjabbli se jiġu msejħa gradi, kif implikat hawnhekk.

1499
01:06:49,100 --> 01:06:53,080
Iżda l-biċċa biss ta 'sintassi ġdid imbagħad huma dawn il-parentesi kwadri, il-fatt

1500
01:06:53,080 --> 01:06:59,350
li stajt qal gradi float u mbagħad parentesi miftuħa u mbagħad numru.

1501
01:06:59,350 --> 01:07:02,460
Avviż, jekk dan huwa kostanti, din hija biss bħal għamilna dan.

1502
01:07:02,460 --> 01:07:06,890
Dan ifisser kompjuter ħej, agħti lili 2 sufruni, u ejja kollettivament sejħa

1503
01:07:06,890 --> 01:07:08,220
minnhom gradi.

1504
01:07:08,220 --> 01:07:11,920
Dan huwa b'kuntrast għal proċess ferm aktar tedious bħal dan.

1505
01:07:11,920 --> 01:07:15,850
Float grade1, float Grade2, u oħrajn.

1506
01:07:15,850 --> 01:07:20,010
Allura firxa jippermetti li jimplimentaw din l-idea, iżda ħafna inqas messily, b'mod

1507
01:07:20,010 --> 01:07:24,630
b'tali mod li nistgħu jikteb linja waħda tal-kodiċi minflok, jiġifieri, 16 għal 16

1508
01:07:24,630 --> 01:07:25,740
semestru ġimgħa.

1509
01:07:25,740 --> 01:07:29,950
So I ma riedx li hard-kodiċi 2 għaliex jekk inti taħseb dwar dan issa

1510
01:07:29,950 --> 01:07:34,160
loġikament - jissoponi sena d-dieħla CS50 tibdil 3 kwizzijiet minflok.

1511
01:07:34,160 --> 01:07:35,510
U kelli in-numru 2 hawn.

1512
01:07:35,510 --> 01:07:36,600
Kelli in-numru 2 hawn.

1513
01:07:36,600 --> 01:07:37,580
Kelli in-numru 2 hawn.

1514
01:07:37,580 --> 01:07:38,560
Kelli in-numru 2 hawn.

1515
01:07:38,560 --> 01:07:43,180
Dan isir ħafna tedious ħafna u faċli biex screw up u aċċidentalment bidla

1516
01:07:43,180 --> 01:07:47,690
valur wieħed sa 3 u titlifx xi valur ieħor ta '2.

1517
01:07:47,690 --> 01:07:52,460
Allura jien ser minflok astratti dan bogħod u jużaw dan kostanti li, kif tagħha

1518
01:07:52,460 --> 01:07:54,120
isem jissuġġerixxi, qatt bidliet.

1519
01:07:54,120 --> 01:07:57,710
U issa, l-ebda kwistjoni jekk aħna jkollniex differenti kwizzijiet din is-sena jew li jmiss, I

1520
01:07:57,710 --> 01:08:01,210
biss għandhom jibdlu f'post wieħed, up hawn fuq quċċata.

1521
01:08:01,210 --> 01:08:02,720
>> Allura li kollox kostanti huwa.

1522
01:08:02,720 --> 01:08:08,680
Sadanittant, il-karatteristika kunċettwali ġdida hija dik ta 'firxa.

1523
01:08:08,680 --> 01:08:14,660
Allura l-parentesi kwadri jagħtu me dan sufruni ħafna u tikri me kollettivament

1524
01:08:14,660 --> 01:08:16,630
jsejħulhom gradi hawnhekk.

1525
01:08:16,630 --> 01:08:17,990
Allura issa ejja ara dak li jien ser tagħmel.

1526
01:08:17,990 --> 01:08:20,359
Hawnhekk fil-linja 24 hija l-bidu ta 'għall-loop.

1527
01:08:20,359 --> 01:08:22,260
Dan huwa verament fancy xejn.

1528
01:08:22,260 --> 01:08:25,060
Huwa biss bl-użu kwizzijiet minflok ta 'numru hard-kodifikati.

1529
01:08:25,060 --> 01:08:27,790
Iżda hemm xejn intellettwalment differenti hemmhekk minn ġimgħa li għaddiet.

1530
01:08:27,790 --> 01:08:29,040
Dan huwa biss printf.

1531
01:08:29,040 --> 01:08:35,490
Allura printf ("Numru kwizz% d% tal d") minħabba I biss trid li jistampa tagħti me kwizz

1532
01:08:35,490 --> 01:08:38,050
numru wieħed ta 'tnejn u mbagħad tnejn minn tnejn.

1533
01:08:38,050 --> 01:08:39,850
Allura dan huwa purament ħaġa estetika.

1534
01:08:39,850 --> 01:08:42,500
Imma l-parti interessanti issa huwa konformi 27.

1535
01:08:42,500 --> 01:08:48,310
Sabiex jimtlew f'wieħed mill-placeholders 2 ma 'varjabbli punt

1536
01:08:48,310 --> 01:08:51,029
valur, għandek terġa 'tuża parentesi kwadri.

1537
01:08:51,029 --> 01:08:55,620
F'dan il-każ, jien jużaw i, minħabba dan għal loop bdiet ma i daqs

1538
01:08:55,620 --> 01:08:57,560
dak il-valur, apparentement?

1539
01:08:57,560 --> 01:08:58,279
0.

1540
01:08:58,279 --> 01:09:01,350
>> Allura fuq l-ewwel iterazzjoni ta 'dan loop, huwa daqs li kieku I

1541
01:09:01,350 --> 01:09:02,689
kiteb dan fil-kodiċi.

1542
01:09:02,689 --> 01:09:05,580
Imma fuq il-tieni iterazzjoni ta 'dan loop, huwa daqs li kieku I

1543
01:09:05,580 --> 01:09:07,750
kiteb dan fil-kodiċi tiegħi.

1544
01:09:07,750 --> 01:09:10,750
Imma l-fatt li jien jużaw varjabbli hi perfetta għaliex, bħala l-isem

1545
01:09:10,750 --> 01:09:14,300
jissuġġerixxi, huwa jvarja valur tiegħu fuq kull iterazzjoni.

1546
01:09:14,300 --> 01:09:17,370
Allura jien mili dan array wieħed post kull darba.

1547
01:09:17,370 --> 01:09:18,910
Xi jfisser dan array look like?

1548
01:09:18,910 --> 01:09:21,430
Ukoll, ir-raġuni I ġibdet dan ir-rettangolu sempliċi super fuq l-iskrin hawn

1549
01:09:21,430 --> 01:09:23,350
qabel kien għal din ir-raġuni.

1550
01:09:23,350 --> 01:09:27,279
Firxa hija biss blokki ta 'memorja segwita minn blokki ta' memorja,

1551
01:09:27,279 --> 01:09:30,109
segwita minn blokki ta 'memorja, u oħrajn.

1552
01:09:30,109 --> 01:09:35,260
Mela jekk firxa tiegħi huwa ta 'daqs 2, f'dan il-każ hawnhekk, kollha I jkun qed jagħmel mill

1553
01:09:35,260 --> 01:09:37,590
ittajpjar fid punteġġi kwizz tiegħi, nixtieq hawnhekk.

1554
01:09:37,590 --> 01:09:39,430
Sibt 100 fuq dan wieħed.

1555
01:09:39,430 --> 01:09:42,020
U mbagħad Sibt 99 dwar dan wieħed.

1556
01:09:42,020 --> 01:09:46,040
Imbagħad din il-memorja ma jista 'anke jkun użat għaliex stajt biss talab lill-

1557
01:09:46,040 --> 01:09:48,689
kompjuter għal firxa ta 'daqs 2.

1558
01:09:48,689 --> 01:09:50,180
Dawk kwadri għadhom hemm.

1559
01:09:50,180 --> 01:09:50,340
Dritt?

1560
01:09:50,340 --> 01:09:52,500
Inti xorta jkollhom żewġ gigabytes ta 'RAM, anki jekk int biss

1561
01:09:52,500 --> 01:09:53,979
titlob għal żewġ sufruni.

1562
01:09:53,979 --> 01:09:58,710
Allura l-idea wara arrays hija li l-kompjuter biss tieħu blokki ta 'memorja

1563
01:09:58,710 --> 01:10:03,230
u mbagħad tqassam biċċiet iżgħar lura lura lura lura.

1564
01:10:03,230 --> 01:10:04,740
U hekk li kollox firxa hija.

1565
01:10:04,740 --> 01:10:09,080
Huwa blokki kontigwi ta 'memorja, minn ġewwa illi inti tista' tpoġġi l-affarijiet.

1566
01:10:09,080 --> 01:10:12,400
>> Issa dan jiġri mbagħad tagħmel biss ftit aritmetika boring.

1567
01:10:12,400 --> 01:10:16,170
Jekk I iscroll stabbiliti hawn, dan huwa fejn I imbagħad ttenni fuq il-firxa.

1568
01:10:16,170 --> 01:10:19,410
I toħroġ bi l-għadd totali tal-valuri kollha fil-firxa.

1569
01:10:19,410 --> 01:10:22,390
U mbagħad I tuża l-funzjoni round hawn biex fil-fatt jagħmlu l-

1570
01:10:22,390 --> 01:10:23,940
somma diviż bil kwiżż.

1571
01:10:23,940 --> 01:10:27,450
Imma ħalluni mewġa naħa tiegħi f'dak bħala tip ta 'aritmetika biżżejjed għal issa.

1572
01:10:27,450 --> 01:10:30,010
Imma dak kollu li qed jagħmel għalija finalment qed jinħadem medja.

1573
01:10:30,010 --> 01:10:33,640
Kwizz Allura l-ewwel plus kwizz 2, diviż bi 2, u mbagħad l-istampar

1574
01:10:33,640 --> 01:10:34,700
it out bħala int.

1575
01:10:34,700 --> 01:10:39,030
>> Imma ejja issa transizzjoni lejn eżempju differenti msejħa string1,

1576
01:10:39,030 --> 01:10:42,370
li żebgħa stampa simili iżda kordi jużaw.

1577
01:10:42,370 --> 01:10:45,550
Let me imorru quddiem u ssimplifikat għal ftit mument.

1578
01:10:45,550 --> 01:10:48,340
U nahfru l-indentazzjoni għal issa.

1579
01:10:48,340 --> 01:10:52,280
Avviż fil-linja 19 ta 'dan eżempju, I nikseb string mill-utent.

1580
01:10:52,280 --> 01:10:55,780
Imma avviż dak li jien tagħmel li jmiss fil-linji 22 'il quddiem.

1581
01:10:55,780 --> 01:11:00,260
Jien fil-fatt mtennija mis i sa - u dan huwa trick ġdid -

1582
01:11:00,260 --> 01:11:02,730
strlen tul string,.

1583
01:11:02,730 --> 01:11:07,010
Din hija funzjoni li jiġi ma C li jekk inti tgħaddi din string, hija jgħidlek

1584
01:11:07,010 --> 01:11:08,950
inti kemm karattri huma f'dak sekwenza.

1585
01:11:08,950 --> 01:11:09,440
Li kollox.

1586
01:11:09,440 --> 01:11:12,520
Il-fatt li huwa strlen minflok it-tul sekwenza huwa biss għaliex dan huwa

1587
01:11:12,520 --> 01:11:13,040
aktar konċiż.

1588
01:11:13,040 --> 01:11:17,100
30 sena ilu, in-nies xtaqu li jiktbu l-affarijiet kif konċiż possibbli.

1589
01:11:17,100 --> 01:11:19,080
Allura konna tinżamm dik il-konvenzjoni hawn.

1590
01:11:19,080 --> 01:11:21,730
i + + ifisser biss inkrement i f'kull iterazzjoni.

1591
01:11:21,730 --> 01:11:24,310
U issa Avviż dan, li huwa verament interessanti.

1592
01:11:24,310 --> 01:11:28,730
Allura fil-linja 24, I say kompjuter, agħti lili karattru, 8

1593
01:11:28,730 --> 01:11:30,770
bits, u sejħa hija ċ.

1594
01:11:30,770 --> 01:11:35,370
Imma dak li hu dan fuq il-lemin tgħid?

1595
01:11:35,370 --> 01:11:38,150
Bl-Ingliż, dak li ma jirrappreżenta?

1596
01:11:38,150 --> 01:11:40,070
[Inaudible]

1597
01:11:40,070 --> 01:11:40,490
DAVID J. Malan: Eżattament.

1598
01:11:40,490 --> 01:11:42,390
Agħti lili l-ewwel karattru fil-firxa.

1599
01:11:42,390 --> 01:11:45,400
Jew b'mod iktar ġenerali, agħti lili il-karattru i-th fil-firxa.

1600
01:11:45,400 --> 01:11:48,230
U jirrealizzaw huwa importanti issa li bħala xjenzjati tal-kompjuter, aħna qed attwalment

1601
01:11:48,230 --> 01:11:49,330
jingħaddu minn 0.

1602
01:11:49,330 --> 01:11:51,290
Inti ma għandekx diskrezzjoni issa biex tibda tagħmel dan.

1603
01:11:51,290 --> 01:11:54,580
Issa għandek biex jaġixxu b'mod konformi mal-aspettattivi tal-kompjuter u

1604
01:11:54,580 --> 01:11:58,010
għadd minn żero minħabba [0] se tkun l-ewwel

1605
01:11:58,010 --> 01:11:59,670
karattru string.

1606
01:11:59,670 --> 01:12:01,320
[1] se jkun it-tieni.

1607
01:12:01,320 --> 01:12:03,610
[2] se tkun it-tielet, u oħrajn.

1608
01:12:03,610 --> 01:12:08,840
Allura dan il-programm, jekk I josservawha - dan huwa, għal darb'oħra, string1.

1609
01:12:08,840 --> 01:12:11,040
>> Sabiex tagħmel string1.

1610
01:12:11,040 --> 01:12:16,730
U issa I run string1 fil tieqa terminal tiegħi.

1611
01:12:16,730 --> 01:12:19,180
Huwa stennija għall-input, hekk jien ser tip fil, jiġifieri, David.

1612
01:12:19,180 --> 01:12:20,080
Ikteb.

1613
01:12:20,080 --> 01:12:23,350
U issa prints DAVID kollha fuq linji differenti minħabba

1614
01:12:23,350 --> 01:12:24,430
Avviż dak li qed nagħmel.

1615
01:12:24,430 --> 01:12:27,510
Jien istampar karattru wieħed fi żmien.

1616
01:12:27,510 --> 01:12:29,100
Issa aħna mhux se tidħol fis-dettal llum dwar dan.

1617
01:12:29,100 --> 01:12:31,610
Imma I imħassar mument ilu dan il-kontroll hawnhekk.

1618
01:12:31,610 --> 01:12:36,310
Jirriżulta li jekk l-utent ikun misbehaving, kontradittorju, jew biss

1619
01:12:36,310 --> 01:12:41,780
konfuż, inti tista 'attwalment jonqsu milli jagħtu sensiela ta' xi tul.

1620
01:12:41,780 --> 01:12:43,640
Jekk inti hit-ċavetta żbaljata fuq il-keyboard, inti tista 'tagħti

1621
01:12:43,640 --> 01:12:44,390
ebda string fil-livelli kollha.

1622
01:12:44,390 --> 01:12:47,790
Jew jekk int malizzjużi, inti tista 'tipprova li paste fil jiswew gigabyte ta' l

1623
01:12:47,790 --> 01:12:49,380
essay biex timla din is-sekwenza.

1624
01:12:49,380 --> 01:12:52,060
U jekk il-kompjuter runs out ta 'memorja, jirriżulta li aħna qed tmur

1625
01:12:52,060 --> 01:12:54,310
li terġa 'lura dan il-valur speċjali msejħa null.

1626
01:12:54,310 --> 01:12:57,550
Allura għal issa, biss jafu li hemm dan il-valur speċjali msejħa null li

1627
01:12:57,550 --> 01:13:01,000
se jippermetti magħna biex jiċċekkja meta nkunu barra ta 'memorja, fost affarijiet oħra.

1628
01:13:01,000 --> 01:13:07,330
>> Imma jekk jien jiftħu issa string2, avviż wieħed differenza hawn.

1629
01:13:07,330 --> 01:13:09,760
Avviż wieħed differenza hawn ma string2.

1630
01:13:09,760 --> 01:13:13,260
Ma string2, dan għal loop huwa xi ftit differenti.

1631
01:13:13,260 --> 01:13:16,350
Let me tħassar il-nulls sabiex inkunu nistgħu nitkellmu dwar dawk ieħor żmien.

1632
01:13:16,350 --> 01:13:18,460
Imma x'hemm differenti dwar il-linja għal dan iż-żmien?

1633
01:13:21,580 --> 01:13:23,160
U I tista 'tmur lura għall-eżempju preċedenti.

1634
01:13:23,160 --> 01:13:24,800
Allura dak verżjoni 2.

1635
01:13:24,800 --> 01:13:27,020
Din hija verżjoni waħda.

1636
01:13:27,020 --> 01:13:31,935
Wieħed, tnejn, li waħda tnejn.

1637
01:13:35,030 --> 01:13:38,240
Allura l-sejħa strlen huwa fejn?

1638
01:13:38,240 --> 01:13:40,420
Huwa fl-ewwel parti tal-linja għall.

1639
01:13:40,420 --> 01:13:43,060
Kwalunkwe ħsibijiet dwar għaliex jien tagħmel dan?

1640
01:13:43,060 --> 01:13:43,690
Yeah.

1641
01:13:43,690 --> 01:13:46,010
[Inaudible]

1642
01:13:46,010 --> 01:13:47,630
DAVID J. Malan: Allura aħna ma sejħa tal-funzjoni kull wieħed ħin.

1643
01:13:47,630 --> 01:13:48,040
Eżattament.

1644
01:13:48,040 --> 01:13:50,350
Recall minn għal linji li dawn qed super sempliċi ladarba tal sort inti

1645
01:13:50,350 --> 01:13:52,180
jifhmu li dan huwa l-inizjalizzazzjoni, il-

1646
01:13:52,180 --> 01:13:53,330
kondizzjoni, u l-aġġornament.

1647
01:13:53,330 --> 01:13:55,430
Il-problema hija li l-kundizzjoni jiġri fuq kull

1648
01:13:55,430 --> 01:13:56,600
iterazzjoni tal-linja.

1649
01:13:56,600 --> 01:13:59,930
U hekk f'dan l-eżempju hawn, dak li huwa ħażin dwar il-fatt

1650
01:13:59,930 --> 01:14:03,500
li dan huwa kundizzjoni tiegħi?

1651
01:14:03,500 --> 01:14:05,920
Inti ssejjaħ strlen ġdid u għal darb'oħra u għal darb'oħra.

1652
01:14:05,920 --> 01:14:08,990
Imma ladarba stajt ittajpjat fil DAVID, it-tul ta 'dak sekwenza huwa 5.

1653
01:14:08,990 --> 01:14:11,560
U huwa mhux se jibdlu fuq kull iterazzjoni tal-linja minħabba li l-

1654
01:14:11,560 --> 01:14:15,560
sekwenza għadu D-A-V-I-D. Allura dan huwa ħjiel fuq dak li għaddej biex issir

1655
01:14:15,560 --> 01:14:19,650
idea dejjem aktar importanti magħruf bħala deċiżjoni disinn, fejn - biss ma

1656
01:14:19,650 --> 01:14:21,640
jagħmlu l-kompjuter jagħmlu x-xogħol bla bżonn.

1657
01:14:21,640 --> 01:14:25,630
>> Issa biss bħala Sneak preview tal pset 2, pset 2 fl-edizzjoni standard huwa

1658
01:14:25,630 --> 01:14:28,850
se jikkontestaw inti fil-fatt jimplimentaw xi numru ta 'ciphers, xi

1659
01:14:28,850 --> 01:14:32,650
numru ta 'algoritmi encryption, sabiex inti tista' kemm kriptaġġ u decrypt

1660
01:14:32,650 --> 01:14:35,530
messaġġi sigrieti, ħafna bħall-Ralphie waħda hemm decoded.

1661
01:14:35,530 --> 01:14:38,720
Fl-edizzjoni Hacker ta pset 2, aħna qed tmur biex tmur ftit aktar.

1662
01:14:38,720 --> 01:14:42,010
Aħna qed tmur biex inti idejn fajl minn sistema tal-kompjuter attwali li fih

1663
01:14:42,010 --> 01:14:45,690
mazz sħiħ ta 'usernames u passwords encrypted attwali, u l-isfida

1664
01:14:45,690 --> 01:14:49,110
għall-edizzjoni Hacker se tkun li jitwaqqaf dawk passwords u l-figura

1665
01:14:49,110 --> 01:14:53,060
barra dak kriptografija jew dak sigriet kien użat biex attwalment

1666
01:14:53,060 --> 01:14:55,080
jiġġeneraw dawk passwords.

1667
01:14:55,080 --> 01:14:58,360
U aħna qed tmur biex tagħmel dan billi tuża fattur ġdid hawn 'C li jien ser jagħtu

1668
01:14:58,360 --> 01:15:02,200
inti biss demo ta ', magħrufa bħala kmand tal-linja argumenti.

1669
01:15:02,200 --> 01:15:05,930
>> Għalhekk jirriżulta, kif xi wħud minnkom tista raw fis-sezzjoni jew fil-kotba,

1670
01:15:05,930 --> 01:15:09,850
prinċipali ma dejjem għandhom ikunu nulli fil-parentesi.

1671
01:15:09,850 --> 01:15:14,060
Jirriżulta li ewlieni tista 'wkoll tkun bil-miktub bħal dan, ma' żewġ argumenti,

1672
01:15:14,060 --> 01:15:19,690
argc u ARGV, fejn argc huwa n-numru ta 'kliem li inti tip wara

1673
01:15:19,690 --> 01:15:21,940
Isem tal-programm fuq linja tal-kmand tiegħek.

1674
01:15:21,940 --> 01:15:24,550
U ARGV huwa l-kliem attwali.

1675
01:15:24,550 --> 01:15:29,470
U kif il-parentesi kwadri hemmhekk jissuġġerixxu, ARGV hija apparentement firxa.

1676
01:15:29,470 --> 01:15:33,720
Huwa ser tkun string wara string wara string fil-memorja.

1677
01:15:33,720 --> 01:15:36,170
Allura dak li aħna qed tmur biex tkun tista 'tagħmel, li tibda bil pset 2, huwa

1678
01:15:36,170 --> 01:15:37,310
xi ħaġa bħal din.

1679
01:15:37,310 --> 01:15:42,450
Jekk I jagħmlu argv1, li huwa eżempju aħna ser terga 'lura għal nhar it-Tnejn, u run

1680
01:15:42,450 --> 01:15:45,180
dan, avviż li ma jidhirx li tagħmel xejn s'issa.

1681
01:15:45,180 --> 01:15:47,050
Hija biss tistampa f'isimha.

1682
01:15:47,050 --> 01:15:53,220
Imma jekk jien ngħid addiju klassi, avviż li dan il-programm apparentement ttenni

1683
01:15:53,220 --> 01:15:57,030
fuq kull wieħed mill-kliem li kienu ittajpjat fil-pront.

1684
01:15:57,030 --> 01:16:02,050
U l-mezzi li bihom aħna se jiksbu aċċess għal kliem li l-utent ikollu

1685
01:16:02,050 --> 01:16:06,780
ttajpjati fil-pront hija billi jbiddlu prinċipali, li jibda dan il-weekend, minn int

1686
01:16:06,780 --> 01:16:10,710
prinċipali (vojt) li int prinċipali (argc, ARGV).

1687
01:16:10,710 --> 01:16:13,700
U għalhekk se tkun imwielda argumenti kmand tal-linja.

1688
01:16:13,700 --> 01:16:17,210
U ladarba ikollok verament sofistikati fil dan, inti ser tkun tista 'tikteb

1689
01:16:17,210 --> 01:16:21,370
Programmi verament trippy, bħal dan wieħed hawn, li tmur fuq u lil hinn

1690
01:16:21,370 --> 01:16:25,520
xi wħud mill-funzjonalità aħna ghamilt s'issa imma kollha pjuttost qawwija.

1691
01:16:25,520 --> 01:16:27,330
>> Allura aħna ser tħalli dan ma 'dan fuq l-iskrin.

1692
01:16:27,330 --> 01:16:29,160
U aħna se tara inti nhar it-Tnejn.