Programming Methodology-Lecture04

ProgrammingMethodology-Lecture04Instructor(MehranSahami):Sowelcomeback.Nowwe抮eofficiallystartedwiththeclass.Ihopeyouhadagoodweekend.Iwasjustaskingpeoplebeforeclasswhatkindofstufftheydidthisweekend.Soifanyonewantsto,comeearly.We抣ljustengageinrandomconversation.Soacoupleofquickannouncements:There抯onehandout,whichisyoursectionhandoutforthisweek.Makesureyougetthat.WhatI抣ldoeveryweekthatwehaveasection,isthatweek,you抣lgetahandoutonMonday,whichisaproblemthatyou抮egoingtogooverinsection.Thisgivesyouachancetothinkaboutitbeforesection.It抯notrequiredthatyoudoit.It抯notextrahomework;it抯justsomethingandifyouwanttoreadthroughittogetfamiliarwithwhatyouwanttodowithsectionorpossiblydoityourselfifyouwantmorepracticetobepreparedforsection,youcandothatandthenyou抣lgotosection;you抣lcovertheproblemandactuallyinsection,you抣lgetsolutionstotheproblem,aswell,soyou抣lgetexamplesofcodeforallthesectionproblems.Sectionassignments?hopefullyyoushouldhavesignedup.ThedeadlineforsigningupwasSundayat5:00p.m.Sectionassignmentswillbemailedouttoyoutomorrownightsoyou抣lknowwhichsectionyou抳ebeenassignedtoandyoucangotosectionsthisweek,getyoursectionleader抯emailaddress,completeAssignment1,atleasttheemailpartbysendingemail,andIdon抰needtomentionthesectionsactuallystartthisweek,soyoushouldgothisweekonceyougetyoursectionassignment.Ifforwhateverreasonyoudidn抰managetosignupforasection,youshouldremedytheproblembyemailingcs198@csandletthemknowyouforgotsign-upforasectionforCS106aandthey抣lletyouknowwhattimesareavailableandyoucansignup.Don抰emailmebecauseIhavenothingtodowiththesections,otherthanactuallyassigningtheproblemsforthesection.Don抰emailBenbecausehe抯notinvolvedinadministrationforthesectionseither.Healsoworriesaboutthecontentofthesections.Butthe198folkshandlealltheadministration.Uh-huh?Student:[Inaudible]Instructor(MehranSahami):Yeah,youshouldsubmititagainafteryou抳ebeenassignedtoasectionjusttoclarify.Allright,butifyou抳ealreadysubmittedit,wecansortfigureitouteventually,butit抯inyourbestinteresttore-submititafteryou抳ebeenassignedtoasection.Soanyquestionsaboutanythingelsebeforewestart?Uh-huh.Student:[Inaudible].Instructor(MehranSahami):Yeah,themostsubmissionistheonethat抯countedifyousubmitmultipletimes.Itjustletsyoukindofsubmitmoreifyou抎like,ifyousubmitsomethingandyou抮elike,揙h,Imadeamistake.?Thenyoucangobackandsubmitagain.Wedon抰feellike,揙h,everytimeIlikesave,Ineedtosubmit.?Don抰worry;justsubmitwhenyoufeellikeyou抮edoneandifyouneedtogobackandmakechanges,that抯fine.Uh-huh?Student:[Inaudible].Instructor(MehranSahami):Ifit抯reallynecessaryandthemainthingisifthere抯spaceinothersections.Yeah,[e-mail]抯goaheadandgetstartedwiththeactualcontent.Andsotodayisthedaywherewemakealittlebitofatransition.It抯likeoneofourtransitionpointsinlife.It抯kindoflikecomingtocollege.AndthetransitionpointwemakeisyounowcomeintotheJavaworld,andyou抮elike,揃utI'mstilldoingKarel.?Yeah,inlectures,we抮egoingtostarttowavebyebyetoKarelandKarel抯like,揧eah,I抣lbethereinyourdreamswhenyou抮eactuallyprogramming,right.?SoKarel抯notreallygoneuntilyou抮edonewiththeAssignmentNo.1.Butnow,wetake?wesortofgraduateintotheworldofJavaandyou抣lactuallyseethatalotofthingsthatexistsinKarel抯worldwillcomebackbecausewegivethemtoinagentleforminKarel抯worldandthentheJavaworld,theycomefullsteam.Sobeforewediveintothat,Iwantyoutogetalittlenotionofthehistoryofcomputing.Okay,andwe抣lgooverthisverybriefly,butcomputingactuallyhasaverylonghistoryanditdatesbackabout4,000years,okay.Soroughly4,000yearsago,thefirstonewethinkofiscomputingdevicewasmadeavailable,butthenyouwanttoknowwhatthatwas?Advocates.Thefirstcomputingdeviceallowedyoutodosomefairlyrudimentaryarithmeticonit,butitactuallywassomethingthatallowedpeopletocomputealotfasterthantheycouldbykeepingtrackofstuffintheirhead.Therealsortofadvancesinwhatwethinkofascomputingactuallycamearoundinthe1800抯.ThatwassomeonebythenameCharlesBabbage.AnyoneheardofCharlesBabbage,bytheway,ajustquickshowofhands.WecanjustcallhimChuck.Hewasactuallyaverywelllearnedandwell-knownpersoninhisday.HehadtheLucasianchair,whichisthesamechairatuniversitythatactuallyStevenHawkinghasnowthatSirIsaacNewtonhadatonepoint.So,prettysmartdude,andhecameupwiththisnotionofsomethingcalledtheDifferenceEngine,whichisawayofbeingabletoautomatically.Andinthosedays,right,theydidn抰havesilicon.Well,theyhadsilicon,butitwasintheformofsand,andtheydidn抰havecomputersinthewaywethinkofcomputers,sohewantedtobuildamechanicaldevicelikewithreal,actual,youknow,mechanicsandpiecesofwoodsthat抯beenaround,andinhistime,hethoughtiswouldbepoweredbysteam,right,becausethisissortofprethinkingaboutelectroniccomputersthatwoulddoautomatedcalculation.AndhedesignedsomethingcalledtheDifferenceEngineandthenhedesignedsomethingcalledtheAnalyticEngine,whichwassupposedtobeevenmorepowerful,andinterestinglyenoughneitheroneofthemwasactuallybuiltduringhislifetime.Itturnsoutthatyearslater,thedifferenceenginewasactuallybuiltfromabunchofwheelsandrotorsandstuffandnowthethings,youknow,thathewouldhavelikedtothinkofastheAnalyticEngineisactuallythesepuppi