Module03-面向对象编程.docx

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1、CopyrightTarenaCorporation,2008.AllrightsreservedModule03-面向对象编程一、选择题：Question1Given:20.publicclassCreditCard{21.22.privateStringcardlD;23.privateIntegerlimit;24.publicStringownerName;25.26.publicvoidsetCardlnformation(StringcardlD,27.StringownerName,28.

2、Integerlimit){29.this.cardlD=cardlD;30.this.ownerName=ownerName;31.this.limit=limit;32.}33.}Whichistrue?A.Theclassisfullyencapsulated.B.Thecodedemonstratespolymorphism.C.TheownerNamevariablebreaksencapsulation.D.ThecardlDandlimitvariablesbreakpolymorphis

3、m.E.ThesetCardlnformationmethodbreaksencapsulation.Answer:CQuestion2Whichtwoaretrue?(Choosetwo.)A.Anencapsulated,publicclasspromotesre-use.B.Classesthatsharethesameinterfacearealwaystightlyencapsulated.C.Anencapsulatedclassallowssubclassestooverloadmetho

4、ds,butdoesNOTallowoverridingmethods.D.Anencapsulatedclassallowsaprogrammertochangeanimplementationwithoutaffectingoutsidecode.Answer:ADQuestion3Assumethatcountryissetforeachclass.Given:10.publicclassMoney{11.privateStringcountry,name;12.publicgetCountry(

5、){returncountry;}CopyrightTarenaCorporation,2008.Allrightsreserved13.}and:24.classYenextendsMoney{25.publicStringgetCountry(){returnsuper.country;}26.}27.28.classEuroextendsMoney{29.publicStringgetCountry(StringtimeZone){30.returnsuper.getCountry();31.}3

6、2.}Whichtwoarecorrect?(Choosetwo.)A.Yenreturnscorrectvalues.B.Euroreturnscorrectvalues.C.Anexceptionisthrownatruntime.D.YenandEurobothreturncorrectvalues.E.Compilationfailsbecauseofanerroratline25.F.Compilationfailsbecauseofanerroratline30.Answer:BEQuest

7、ion4Given:10.interfaceA{voidx();}11.classBimplementsA{publicvoidx(){}publicvoidy(){}}12.classCextendsB{publicvoidx(){}}And:20.java.util.Listlist=newjava.util.ArrayList();21.list.add(newB());22.list.add(newC());23.for(Aa:list){24.a.x();25.a.y();26.}

8、Whatistheresult?A.Thecoderunswithnooutput.B.Anexceptionisthrownatruntime.C.Compilationfailsbecauseofanerrorinline20.D.Compilationfailsbecauseofanerrorinline21.E.Compilationfailsbecauseofanerrorinline23.F.Compilationfailsbe