c++编程外文文献Word下载.docx

c++编程外文文献Word下载.docx

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c++编程外文文献@#@附件一外文原文@#@Object-OrientationandC++@#@C++isjustoneofmanyprogramminglanguagesinusetoday.Whyaretheresomanylanguages?

@#@Whydonewonesappeareveryfewyears?

@#@Programminglanguageshaveevolvedtohelpprogrammerseasethetransitionfromdesigntoimplementation.@#@Thefirstprogramminglanguageswereverydependentontheunderlyingmachinearchitecture.Writingprogramsatthislevelofdetailisverycumbersome.Justashardwareengineerslearnedhowtobuildcomputersystemsoutofothercomponents,languagedesignersalsorealizedthatprogramscouldbewrittenatamuchhigherlevel,therebyshieldingtheprogrammerfromthedetailsoftheunderlyingmachine.@#@Whyaretheresuchalargenumberofhigh-levelprogramminglanguages?

@#@Therearelanguagesforaccessinglargeinventorydatabases,formattingfinancialreports,controllingrobotsonthefactoryfloor,processinglists,controllingsatellitesinrealtime,simulatinganuclearreactor,predictingchangingatmosphericconditions,playingchess,anddrawingcircuitboards.Eachoftheseproblemsrequiresdifferentsetsofdatastructuresandalgorithms.Programminglanguagesaretoolstohelpussolveproblems.However,thereisnotoneprogramminglanguagethatisbestforeverytypeofproblem.Newprogramminglanguagesareoftendevelopedtoprovidebettertoolsforsolvingaparticularclassofproblems.Otherlanguagesareintendedtobeusefulforavarietyofproblemdomainsandaremoregeneralpurpose.@#@Eachprogramminglanguageimpartsaparticularprogrammingstyleordesignphilosophyonitsprogrammers.Withthemultitudeofprogramminglanguagesavailabletoday,anumberofsuchdesignphilosophieshaveemerged.Thesedesignphilosophies,calledprogrammingparadigms,helpustothinkaboutproblemsandformulatesolutions.@#@1.SoftwareDesignthroughParadigms@#@Whendesigningsmallcomputerprogramsorlargesoftwaresystems,weoftenhaveamentalmodeloftheproblemwearetryingtosolve.Howdowedeviseamentalmodelofasoftwaresystem?

@#@Programmingparadigmsoffermanydifferentwaysofdesigningandthinkingaboutsoftwaresystems.Aparadigmcanbethoughtofasamentalmodelorasaframeworkfordesigninganddescribingasoftwaresystem'@#@sstructure.Themodelhelpsusthinkaboutandformulatesolutions.@#@Wecanusethementalmodelofaparadigmindependentlyfromtheprogramminglanguagechosenforimplementation.However,whenthechosenlanguageprovidesconstructsandmechanismsthataresimilartothosethatarefoundintheparadigm,theimplementationwillbemorestraightforward.Usually,thereareseverallanguagesthatbelongtoaparadigm.Forthisreason,aprogrammingparadigmisalsoconsideredaclassoflanguages.@#@Alanguagedoesnothavetofitintojustoneparadigm.Moreoften,languagesprovidefeaturesorcharacteristicsfromseveralparadigms.Hybridlanguages,suchasC++,combinecharacteristicsfromtwoormoreparadigms.C++includescharacteristicsfromtheimperativeandproceduralparadigms--justlikeitspredecessorlanguage,C--andtheobject-orientedparadigm.@#@THEIMPERATIVEPARADIGM.Theimperativeparadigmischaracterizedbyanabstractmodelofacomputerwithalargememorystore.ThisistheclassicvonNeumannmodelofcomputerarchitecture.Computations,whichconsistofasequenceofcommands,arestoredasencodingwithinthestore.Commandsenablethemachinetofindsolutionsusingassignmenttomodifythestore,variablestoreadthestore,arithmeticandlogictoevaluateexpressions,andconditionalbranchingtocontroltheflowofexecution.@#@THEPROCEDURALPARADIGM.Theproceduralparadigmincludestheimperativeparadigm,butextendsitwithanabstractionmechanismforgeneralizingcommandsandexpressionsintoprocedures.Parameters,whichareessentiallyaliasesforaportionofthestore,werealsointroducedbythisparadigm.Otherfeaturesincludeiteration,recursion,andselection.Mostmainstreamsprogrammingtodayisdoneinaprocedurallanguage.@#@Theproceduralparadigmwasthefirstparadigmtointroducethenotionofabstractionintoprogramdesign.Thepurposeofabstractioninprogrammingistoseparatebehaviorfromimplementation.Proceduresareaformofabstraction.Theprocedureperformssometaskorfunction.Otherpartsoftheprogramcalltheprocedure,knowingthatitwillperformthetaskcorrectlyandefficiently,butwithoutknowingexactlyhowtheprocedureisimplemented.@#@THEPROCEDURALPARADIGMWITHADTs.DATAABSTRACTIONisconcernedwithseparatingthebehaviorofadataobjectfromitsrepresentationorimplementation.Forexample,astackcontainstheoperationsPush,Pop,andIsEmpty.Astackobjectprovidesuserswiththeseoperations,butdoesnotrevealhowthestackisactuallyimplemented.Thestackcouldbeimplementedusinganarrayoralist.Usersofthestackobjectdonotcarehowth