毕业论文外文翻译-C#.docx

毕业论文外文翻译-C#.docx

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WhereC#FitsIn

Inonesense,C#canbeseenasbeingthesamethingtoprogramminglanguagesas.NETistotheWindowsenvironment.JustasMicrosofthasbeenaddingmoreandmorefeaturestoWindowsandtheWindowsAPIoverthepastdecade,VisualBasicandC++haveundergoneexpansion.AlthoughVisualBasicandC++haveendedupashugelypowerfullanguagesasaresultofthis,bothlanguagesalsosufferfromproblemsduetothelegaciesofhowtheyhaveevolved.

InthecaseofVisualBasic6andearlier,themainstrengthofthelanguagewasthefactthatitwassimpletounderstandanddidn'tmakemanyprogrammingtaskseasy,largelyhidingthedetailsoftheWindowsAPIandtheCOMcomponentinfrastructurefromthedeveloper.ThedownsidetothiswasthatVisualBasicwasnevertrulyobject-oriented,sothatlargeapplicationsquicklybecomedisorganizedandhardtomaintain.Aswellasthis,becauseVisualBasic'ssyntaxwasinheritedfromearlyversionsofBASIC（which,inturn,wasdesignedtobeintuitivelysimpleforbeginningprogrammerstounderstand,ratherthantowritelargecommercialapplications）,itdidn'treallylenditselftowell-structuredorobject-orientedprograms.

C++,ontheotherhand,hasitsrootsintheANSIC++languagedefinition.Itisn'tcompletelyANSIcompliantforthesimplereasonthatMicrosoftfirstwroteitsC++compilerbeforetheANSIdefinitionhadbecomeofficial,butitcomesclose.Unfortunately,thishasledtotwoproblems.First,ANSIC++hasitsrootsinadecade-oldstateoftechnology,andthisshowsupinalackofsupportformodemconcepts（suchasUnicodestringsandgeneratingXMLdocumentation）,andinsomearchaicsyntaxstructuresdesignedforthecompilersofyesteryear（suchastheseparationofdeclarationfromdefinitionofmemberfunctions）.Second,MicrosofthasbeensimultaneouslytryingtoevolveC++intoalanguagethatisdesignedforhigh-performancetasksonWindows,andinordertoachievethatthey'vebeenforcedtoaddahugenumberofMicrosoft-specifickeywordsaswellasvariouslibrariestothelanguage.

TheresultisthatonWindows,thelanguagehasbecomeacompletemess.JustaskC++developershowmanydefinitionsforastringtheycanthinkof:

char*,LPTSTR,string,CString（MFCversion）,CString（WTLversion）,wchart*,OLECHAR*,andsoon.

Nowenter.NET一acompletelynewenvironmentthatisgoingtoinvolvenewextensionstobothlanguages.MicrosofthasgottenaroundthisbyaddingyetmoreMicrosoft-specifickeywordstoC++,andbycompletelyrevampingVisualBasicintoVisualBasic.NET,alanguagethatretainssomeofthebasicVBsyntaxbutthatissodifferentindesignthatwecanconsiderittobe,forallpracticalpurposes,anewlanguage.IfsinthiscontextthatMicrosofthasdecidedtogivedevelopersanalternative一alanguagedesignedspecificallyfor.NET,anddesignedwithacleanslate.VisualC#.NETistheresult.Officially,MicrosoftdescribesC#asa"simple,modern,object-oriented,andtype-safeprogramminglanguagederivedfrom

CandC++."Mostindependentobserverswouldprobablychangethatto"derivedfromC,C++,andJava."Suchdescriptionsaretechnicallyaccuratebutdolittletoconveythebeautyoreleganceofthelanguage.Syntactically,C#isverysimilartobothC++andJava,tosuchanextentthatmanykeywordsarethesame,andC#alsosharesthesameblockstructurewithbraces（{}）tomarkblocksofcode,andsemicolonstoseparatestatements.ThefirstimpressionofapieceofC#codeisthatitlooksquitelikeC++orJavacode.Behindthatinitialsimilarity,however,C#isaloteasiertolearnthanC++,andofcomparabledifficultytoJava.Itsdesignismoreintunewithmodemdevelopertoolsthanbothofthoseotherlanguages,andithasbeendesignedtogiveus,simultaneously,theeaseofuseofVisualBasic,andthehighperformance,low-levelmemoryaccessofC++ifrequired.SomeofthefeaturesofC#are:

□ Fullsupportforclassesandobject-orientedprogramming,includingbothinterfaceandimplementation

inheritance,virtualfunctions,andoperatoroverloading.

□ Aconsistentandwell-definedsetofbasictypes.

□ Built-insupportforautomaticgenerationofXMLdocumentation.

□ Automaticcleanupofdynamicallyallocatedmemory.

□ Thefacilitytomarkclassesormethodswithuser-definedattributes.Thiscanbeusefulfordocumentation

andcanhavesomeeffectsoncompilation（forexample,markingmethodstobecompiledonlyindebugbuilds）.

□ Fullaccesstothe.NETbaseclasslibrary,aswellaseasyaccesstotheWindowsAPI（ifyou

reallyneedit,whichwon9tbeallthatoften）.

□ Pointersanddirectmemoryaccessareavailableifrequired,butthelanguagehasbeendesigned

insuchawaythatyoucanworkwithouttheminalmostallcases.

□ SupportforpropertiesandeventsinthestyleofVisualBasic.

□ Justbychangingthecompilerop