旅行社计划书范文.doc

旅行社计划书范文 11Introduction toComputers,the Inter and World Wide Web1.7Introduction WhatIs a Computer?Computer OrganizationEarly OperatingSystems Personal,Distributed and Client/Server ComputingThe Inter and the World Wide WebMachine Languages,Assembly Languages and High-Level LanguagesHistory of C and C+C+Standard LibraryHistory of JavaFORTRAN,COBOL,Pascal andAdaBasic,Visual Basic,Visual C+,C#and.NETKey SoftwareTrend:Object TechnologyTypical C+Development EnvironmentNotes About C+and C+How toProgram,5/eTest-Driving aC+ApplicationSoftware EngineeringCase Study:Introduction toObject Technologyand the UML(Required)09Wrap-UpWeb ResourcesOBJECTIVESInthis chapteryou willlearn:?Basic hardwareand softwareconcepts.?Basic object-technology concepts,such asclasses,objects,attributes,behaviors,encapsulation andinheritance.?The differenttypes ofprogramming languages.?Which programming languages aremost widelyused.?A typicalC+program development environment.?The historyof theindustry-standard object-oriented systemmodeling language,theUML.?The historyof theInter and the World Wide Web.?To test-drive C+applications intwo popularC+environmentsGNU C+running onLinux andMicrosofts Visual C+?.NET runningon Windows?XP.1.1Introduction?Software?Instructions tomand puterto perform actions andmake decisions?Hardware?Standardized versionof C+?United States?American NationalStandards Institute(ANSI)?Worldwide?International Organizationfor Standardization(ISO)?Structured programming?Objectoriented programming1.2What is aComputer?Computer?Device capableof performingputations andmaking logicaldecisions?Computer programs?Sets ofinstructions thatcontrol puters processingof data?Hardware?Various devicesprising puter?Keyboard,screen,mouse,disks,memory,CDROM,processing units,?Software?Programs thatrun onputer1.3Computer Organization?Six logicalunits of puter1.Input unit?“Receiving”section?Obtains informationfrom inputdevices Keyboard,mouse,microphone,scanner,works,?2.Output unit?“Shipping”section?Takes informationprocessed byputer?Places informationon outputdevicesScreen,printer,works,?Information usedto controlother devices1.3Computer Organization?Six logicalunits of puter3.Memory unit?Rapid aess,relatively lowcapacity“warehouse”section?Retains informationfrom inputunitImmediately availablefor processing?Retains processedinformationUntil placedon outputdevices?Memory,primary memory4.Arithmetic andlogic unit(ALU)?“Manufacturing”section?Performs arithmetialculations andlogic decisions1.3Computer Organization?Six logicalunits of puter5.Central processingunit(CPU)?“Administrative”section?Supervises andcoordinates othersections ofputer6.Secondary storageunit?Longterm,highcapacity“warehouse”section?Storage?Inactive programsor data?Secondary storagedevicesDisks?Longer toaess than primary memory?Less expensiveper unitthanprimarymemory1.4Early OperatingSystems?Early puters?Singleuser batchprocessing?Only onejob ortask at a time?Process datain groups(batches)?Decks ofpunched cards?Operating systems?Software systems?Manage transitionsbetween jobs?Increased throughput?Amount ofwork putersprocessENIAC,a machinebuilt byJohn Mauchlyand J.Presper Eckertthat improvedby1,000times onthe speedof itscontemporaries.Start ofproject1943Completed:1946Programmed plugboard andswitches Speed5,000operations persecond.1.4Early OperatingSystems?Multiprogramming?Many jobsor taskssharing puters resources?“Simultaneous”operation ofmany jobs?Timesharing?1960s?Special caseof multiprogramming?Users aessputer throughterminals?Devices withkeyboards andscreens?Dozens,even hundredsof users?Perform smallportion ofone users job,then moveson toservice nextuser?Advantage:?User receivesalmost immediateresponses torequests1.5Personal,Distributed and Client/Server Computing?Personal puters?1977:Apple Computer?Economical enoughfor individual?1981:IBM PersonalComputer?“Standalone”units?Computer works?Over telephonelines?Local areaworks(LANs)?Distributed puting?Organizations putingdistributed overworks1.5Personal,Distributed and Client/Server Computing?Workstations?Provide enormouscapabilities?Information sharedacross works?Client/server puting?File servers?Offer monstore ofprograms anddata?Client puters?Aess fileservers acrosswork?UNIX,Linux,Microsofts Windowbased systems1.6The Interand the World Wide Web?Late1960s:ARPA?Advanced ResearchProjects Agency?Department ofDefense?ARPA?Electronic mail(email)?Packet switching?Transfer digitaldata via small packets?Allow multipleusers tosend/receive datasimultaneously oversame municationpaths?No centralizedcontrol?If onepart ofwork fails,other partscan stilloperate1.6The Interand theWorld WideWeb?TCP/IP?Transmission ControlProtocol(TCP)?Messages routedproperly?Messages arrivedintact?Inter Protocol(IP)?Communication amongvariety ofworking hardwareand software?Current architectureof Inter?Bandwidth?Carrying capacityof municationslines1.6The Interand theWorld WideWeb?World WideWeb?1990:Tim BernersLee(CERN)?Locate andview multimediabased documents?Information instantlyand convenientlyaessible worldwide?Possible worldwideexposure?Individuals andsmall businesses?Changing waybusiness done1.6The Interand theWorld WideWeb?WorldWideWeb Consortium(W3C)?1994:Tim BernersLee?Develop nonproprietary,interoperable technologies?Standardization organization?Three hosts?Massachusetts Instituteof Technology(MIT)?Frances INRIA(Institut Nationalde Rechercheen Informatiqueet Automatique)?Keio Universityof Japan?Over400members?Primary financing?Strategic direction1.6TheInterand theWorldWideWeb?Remendations?3phases?Working Draft?Specifies evolvingdraft?Candidate Remendation?Stable versionthat industrycan beginto implement?Proposed Remendation?Considerably matureCandidate Remendation1.7Machine Languages,Assembly Languagesand Highlevel Languages?Three typesofputerlanguages1.Machine languageOnlylanguage puterdirectly understands“Natural language”of puterDefinedby hardwaredesignMachinedependentGenerally consistof stringsof numbersUltimately0sand1sInstruct putersto performelementary operationsOneatatimeCumbersome forhumansExample:+1300042774+1400593419+1xx74027?1.7Machine Languages,Assembly Languagesand Highlevel Languages?Three typesofputerlanguages2.Assembly language?Englishlike abbreviationsrepresenting elementaryputer operations?Clearer tohumans?Inprehensible toputersTranslator programs(assemblers)Convert tomachine language?Example:LOADADD STOREBASEPAYOVERPAYGROSSPAY1.7MachineLanguages,Assembly Languagesand Highlevel Languages?Three typesofputerlanguages3.Highlevel languages?Similar toeveryday English,use monmathematical notations?Single statementsaomplish substantialtasksAssembly languagerequires manyinstructions toaomplish simpletasks?Translator programs(pilers)Convert tomachine language?Interpreter programsDirectlyexecute highlevel languageprograms?Example:grossPay=basePay+overTimePay1.8History of C and C+?History of C?Evolved fromtwo otherprogramminglanguages?BCPL andBKen Thompson1970?“Typeless”languages?Dennis Ritchie(Bell Laboratories)?Added datatyping,other features?Development languageof UNIX?Hardware independent?Portable programs?1989:ANSI standard?1990:ANSI andISO standardpublished?ANSI/ISO9899:19901.8History of C and C+?History of C+?Extension ofC?Early1980s:Bjarne Stroustrup(Bell Laboratories)?“Spruces up”C?Provides capabilitiesfor objectoriented programming?Objects:reusable software ponents?Model itemsin realworld?Objectoriented programs?Easy tounderstand,correct andmodify?Hybrid language?Clike style?Objectoriented style?Both1.8HistoryofC and C+Because Cisastandardized,hardwareindependent,widely availablelanguage,applications writtenin Coften can be runwith littleor nomodification ona widerange ofputer systems.Portability Tip1.11.9C+Standard Library?C+programs?Built frompieces calledclasses and functions?C+standard library?Rich collectionsof existingclasses and functions?“Building blockapproach”to creatingprograms?“Software reuse”1.9C+Standard LibraryUsea“buildingblock”approach tocreate programs.Avoid reinventingthe wheel.Use existingpieces whereverpossible.Called softwarereuse,this practiceis centralto objectoriented programming.Software EngineeringObservation1.11.9C+Standard LibraryWhenprogramming in C+,you typicallywill usethe followingbuilding blocks:Classes andfunctions fromthe C+Standard Library,classes andfunctions youand yourcolleagues createand classes andfunctionsfrom variouspopular thirdparty libraries.Software EngineeringObservation1.21.9C+Standard LibraryUsingC+Standard Libraryfunctions andclasses insteadof writingyour ownversions canimprove programperformance,because theyare writtencarefully toperform efficiently.This techniquealso shortensprogram developmenttime.Performance Tip1.11.9C+Standard LibraryUsingC+Standard Libraryfunctions andclasses insteadof writingyour ownimproves programportability,because theyare includedin everyC+implementation.Portability Tip1.21.10HistoryofJava?Java?1991:Sun Microsystems?Green project?1995:Sun Microsystems?Formally announcedJava attrade show?Web pageswith dynamicand interactivecontent?Develop largescale enterpriseapplications?Enhance functionalityof webservers?Provide applicationsfor consumerdevices?Cell phones,pagers,personal digitalassistants,1.11FORTRAN,COBOL,Pascal andAda?FORTRAN?FORmula TRANslator?19541957:IBM?Complex mathematicalputations?Scientific andengineering applications?COBOL?COmmon BusinessOriented Language?1959:puter manufacturers,government andindustrial puterusers?Precise andefficient manipulationof largeamounts ofdata?Commercial applications1.11FORTRAN,COBOL,Pascal andAda?Pascal?Prof.Niklaus Wirth?Academic use?Ada?Developed underthe sponsorshipof U.S.Department ofDefense(DOD)?Multitasking?Named afterLady AdaLovelace1.12Basic Visual Basic,Visual C+,C#and.NET?BASIC?Beginners AllPurpose SymbolicInstruction Code?Mid1960s:Prof.John Kemenyand ThomasKurtz(Dartmouth College)?Visual Basic?1991?Result ofMicrosoft Windowsgraphical userinterface(GUI)?Developed late1980s,early1990s?Powerful features?GUI,event handling,aess toWin32API,objectoriented programming,error handling?Visual Basic.NET1.12Basic VisualBasic,Visual C+,C#and.NET?Visual C+?Microsofts implementationofC+?Includes extensions?Microsoft FoundationClasses(MFC)?Common library?GUI,graphics,working,multithreading,?Shared amongVisualBasic,Visual C+,C#?.NET platform?Webbased applications?Distributed togreat varietyof devices?Cell phones,desktop puters?Applications indisparate languagescan municate1.12Basic VisualBasic,VisualC+,C#and.NET?C#?Anders Hejlsbergand ScottWiltamuth(Microsoft)?Designed specificallyfor.NET platform?Roots inC,C+and Java?Easy migrationto.NET?Eventdriven,fully objectoriented,visual programminglanguage?Integrated Development Environment(IDE)?Create,run,test anddebug C#programs?Rapid ApplicationDevelopment(RAD)?Language interoperability1.13Key SoftwareTrend:Object Technology?Objects?Reusable softwareponents thatmodel realworld items?Meaningful softwareunits?Date objects,time objects,paycheck objects,invoice objects,audio objects,video objects,file objects,record objects,etc.?Any nouncanberepresented asan object?More understandable,better organizedand easierto maintainthan proceduralprogramming?Favor modularity?Software reuse?Libraries?MFC(Microsoft FoundationClasses)?Rogue Wave1.13Key SoftwareTrend:Object TechnologyExtensiveclass librariesof reusablesoftwareponentsare availableover theInterand theWorldWideWeb.Many ofthese librariesare availableat nocharge.Software EngineeringObservation1.31.13Key SoftwareTrend:Object TechnologyReuseof existingclasses whenbuilding newclasses andprograms savestime,money andeffort.Reuse alsohelps programmersbuild morereliable andeffective systems,because existingclassesandponents oftenhave gohrough extensivetesting,debugging andperformance tuning.Software EngineeringObservation1.41.14Typical C+Development Environment?C+systems?Programdevelopment environment?Language?C+Standard Library1.14Typical C+Development EnvironmentPhasesofC+Programs:1.Edit2.Preprocess3.Compile4.Link5.Load6.Execute1.14Typical C+DevelopmentEnvironment?Input/output?cin?Standard inputstream?Normally keyboard?cout?Standard outputstream?Normally puterscreen?cerr?Standard errorstream?Display errormessages1.14TypicalC+Development EnvironmentErrorslike divisionby zeroour asa programruns,so theyare calledruntime errorsor executiontime errors.Fatal runtimeerrors causeprograms toterminate immediatelywithout havingsuessfully performedtheir jobs.Nonfatal runtimeerrors allowprograms torun topletion,often producingincorrect results.Note:On somesystems,dividebyzero isnot afatal error.Please seeyour systemdocumentation.Common ProgrammingError1.11.15Notes AboutC+andC+How toProgram,5/e?Book gearedtoward noviceprogrammers?Stress programmingclarity?C andC+are portablelanguages?Portability?C andC+programs canrun onmany different puters?Compatibility?Many featuresof currentversions ofC+not patiblewith olderimplementations1.15Notes AboutC+andC+How toProgram,5/eWrite yourC+programs ina simpleand straightforwardmanner.This issometimes referredto asKIS(“keep itsimple”).Do not“stretch”the languageby tryingbizarre usages.Good ProgrammingPractice1.11.15Notes AboutC+andC+How toProgram,5/eAlthough itis possibleto writeportable programs,there aremany problemsamong differentCandC+pilers anddifferentputersthat canmake portabilitydifficult toachieve.Writing programsinCandC+does notguarantee portability.The programmeroften willneed todeal directlywith pilerand putervariations.As agroup,these aresometimes calledplatform variations.Portability Tip1.31.15Notes AboutC+andC+How toProgram,5/eRead themanuals forthe versionofC+you are using.Refer tothese manualsfrequently tobe sureyou areaware ofthe richcollection ofC+features andthat youareusingthem correctly.Good ProgrammingPractice1.21.15NotesAboutC+andC+How toProgram,5/eYour puterand pilerare goodteachers.If afterreading yourC+language manual,you stillare notsure howa featureofC+works,experiment usingasmall“test program”and seewhat happens.Set yourpiler optionsfor“maximum warnings.”Study eachmessage thatthe pilergenerates andcorrect theprograms toeliminate themessages.Good ProgrammingPractice1.31.16TestDriving aC+Application1.16TestDriving aC+Application1.16TestDriving aC+Appl