面向对象程序设计知到智慧树章节测试课后答案2024年秋齐鲁工业大学

面向对象程序设计知到智慧树章节测试课后答案2024年秋齐鲁工业大学第一章单元测试

WhicheditionofJavaisgearedtowarddevelopinglarge-scale,distributednetworkingapplicationsandweb-basedapplications?()

A:EnterpriseEdition.

B:IndustrialEdition.

C:StandardEdition.

D:MicroEdition.

答案:EnterpriseEdition.

Javawasoriginallydevelopedfor:()

A:Distributedcomputing.

B:Operatingsystemsdevelopment.

C:Personalcomputers.

D:Intelligentconsumerdevices.

答案:Intelligentconsumerdevices.

WhichofthefollowingstatementsaboutJavaClassLibrariesisfalse:()

A:Javaclasslibrariesconsistofclassesthatconsistofmethodsthatperformtasks.

B:AnadvantageofusingJavaclasslibrariesissavingtheeffortofdesigning,developingandtestingnewclasses.

C:JavaclasslibrariesarealsoknownasJavaAPIs(ApplicationProgrammingInterfaces).

D:Javaclasslibrariesarenotportable

答案:Javaclasslibrariesarenotportable

The.classextensiononafilemeansthatthefile:()

A:Containsjavasourcecode

B:Noneoftheabove.

C:ContainsHTML

D:isproducedbytheJavacompiler(javac).

答案:isproducedbytheJavacompiler(javac).

Thecommand________executesaJavaapplication.()

A:java

B:run

C:javac

D:Noneoftheabove

答案:java

第二章单元测试

End-of-linecommentsthatshouldbeignoredbythecompileraredenotedusing()

A:Threeforwardslashes(///).

B:Aslashandtwostars(/**).

C:Twoforwardslashes(//).

D:Aslashandastar(/*).

答案:Twoforwardslashes(//).

WhichofthefollowingisnotavalidJavaidentifier?()

A:width

B:myValue

C:$_AAA1

D:m_x

答案:myValue

WhichofthefollowingcannotcauseasyntaxerrortobereportedbytheJavacompiler?()

A:Mismatched{}

B:Missing;

C:Missing*/inacommentthatbeginswith/*

D:Anextrablankline.

答案:Anextrablankline.

Whichofthefollowingdoesnotcontainasyntaxerror?()

A:System.out.println("Helloworld!");

B:System.out.println('Helloworld!'):

C:System.out.println("Hello回车换行world!");

D:System.out.println(Helloworld!);

答案:System.out.println("Helloworld!");

WhichcommandcompilestheJavasourcecodefileWelcome.java?()

A:javacWelcome.java

B:compileWelcome.java

C:javaWelcome.java

D:cdWelcome.java

答案:javacWelcome.java

WhichcommandexecutestheJavaclassfileWelcome.class?()

A:javaWelcome.class

B:runWelcome.class

C:javawelcome

D:javaWelcome

答案:javaWelcome

Whichistheoutputofthefollowingstatements?

()

A:WorldHello

B:HelloWorld

C:HelloWorld

D:HelloWorld

答案:HelloWorld

Whichstatementprintsthefloating-pointvalue123.456rightjustifiedwithafieldwidthof10?()

A:System.out.printf("%d10.3",123.456);

B:System.out.printf("%10.3f",123.456);

C:System.out.printf("%f10.3",123.456);

D:System.out.printf("%10.3d",123.456);

答案:System.out.printf("%10.3f",123.456);

Whatisthesizeinbitsofanint?()

A:8

B:16

C:64

D:32

答案:32

Whichofthefollowingistheescapecharacter?()

A:\

B:"

C:*

D:\n

答案:\

第三章单元测试

Whichofthefollowingcanbeusedinaswitchstatementintheexpressionafterkeywordcase?a.aconstantintegralexpression.b.acharacterconstant.c.aStringd.anenumerationconstant.()

A:aandb.

B:bandc

C:aandc

D:All.

答案:All.

Optionalparenthesesinexpressionsaresaidtobe()

A:binaryoperators.

B:implied.

C:redundant.

D:declared.

答案:redundant.

Whichofthefollowingstatementsdoesnotalterthevaluestoredinamemorylocation?()

A:number=12;

B:width=Integer.parseInt(input);

C:inta;

D:y=y+2;

答案:inta;

WhatisthevalueofresultafterthefollowingJavastatementsexecute(assumeallvariablesareoftypeint)?

()

A:127

B:59

C:119

D:51

答案:119

Whichofthefollowingisnotanarithmeticoperator?()

A:-

B:%

C:.

D:+

答案:.

Whichofthefollowingisnotacompilationerror?()

A:Placingasemicolonattheendofthefirstlineofanifstatement.

B:Neglectingtoinitializealocalvariableinamethodbeforeitisused.

C:Omittingtheleftandrightparenthesisfortheconditionofanifstatement.

D:Allarecompilationerrors.

答案:Placingasemicolonattheendofthefirstlineofanifstatement.

Eachofthefollowingisarelationalorequalityoperatorexcept:()

A:＞

B:＜=

C:==

D:=!

答案:=!

Whichofthefollowingisnotacontrolstructure:()

A:Declarationstructure.

B:Sequencestructure.

C:Repetitionstructure.

D:Selectionstructure.

答案:Declarationstructure.

Whichstatementisfalse?()

A:Unlessdirectedotherwise,thecomputerexecutesJavastatementsoneaftertheotherintheorderinwhichthey'rewritten.

B:ActivitydiagramsnormallyshowtheJavacodethatimplementstheactivity.

C:Likepseudocode,activitydiagramshelpprogrammersdevelopandrepresentalgorithms.

D:Thearrowsintheactivitydiagramrepresenttransitions,whichindicatetheorderinwhichtheactionsrepresentedbytheactionstatesoccur.

答案:ActivitydiagramsnormallyshowtheJavacodethatimplementstheactivity.

Whichofthefollowingisadouble-selectioncontrolstatement?()

A:for

B:if

C:if…else

D:do…while

答案:if…else

第四章单元测试

Thenumberofargumentsinthemethodcallmustmatchthenumberofparametersinthemethoddeclaration’sparameterlist.()

A:错B:对

答案:对Floating-pointvaluesthatappearinsourcecodeareknownasfloating-pointliteralsandaretypefloatbydefault.()

A:对B:错

答案:错Eachclassyoucreatebecomesanew________thatcanbeusedtodeclarevariablesandcreateobjects.()

A:instance

B:package

C:library

D:type.

答案:type.

Whichofthefollowingstatementsisfalse?()

A:Everyclassdeclarationcontainskeywordclassfollowedimmediatelybytheclass’sname.

B:Class,methodandvariablenamesareidentifiers.

C:Eachclassdeclarationthatbeginswiththeaccessmodifierprivatemustbestoredinafilethathasthesamenameastheclassandendswiththe.javafilenameextension.

D:Anobjecthasattributesthatareimplementedasinstancevariablesandcarriedwithitthroughoutitslifetime.

答案:Eachclassdeclarationthatbeginswiththeaccessmodifierprivatemustbestoredinafilethathasthesamenameastheclassandendswiththe.javafilenameextension.

Whichofthefollowingstatementsisfalse?()

A:Byconventionclassnamesbeginwithanuppercaseletter,andmethodandvariablenamesbeginwithalowercaseletter.

B:Instancevariablescanbedeclaredanywhereinsideaclass.

C:Instancevariablesexistbeforemethodsarecalledonanobject,whilethemethodsareexecutingandafterthemethodscompleteexecution.

D:Aclassnormallycontainsoneormoremethodsthatmanipulatetheinstancevariablesthatbelongtoparticularobjectsoftheclass.

答案:Instancevariablescanbedeclaredanywhereinsideaclass.

Whichofthefollowingstatementsistrue?()

A:Variablesormethodsdeclaredwithaccessmodifierprivateareaccessibleonlytomethodsoftheclassinwhichthey’redeclared.

B:Eachobject(instance)oftheclasssharestheclass’sinstancevariables.

C:Noneoftheaboveistrue.

D:Mostinstance-variabledeclarationsareprecededwiththekeywordpublic,whichisanaccessmodifier.

答案:Variablesormethodsdeclaredwithaccessmodifierprivateareaccessibleonlytomethodsoftheclassinwhichthey’redeclared.

Whenamethodterminates,thevaluesofitslocalvariablesare________.()

A:saved

B:copied

C:restored

D:lost

答案:lost

Whichofthefollowingstatementsistrue?()

A:ThedefaultvalueforaninstancevariableoftypeStringisvoid.

B:Theargumenttypesinthemethodcallmustbeidenticaltothetypesofthecorrespondingparametersinthemethod’sdeclaration.

C:Everyinstancevariablehasadefaultinitialvalue—avalueprovidedbyJavawhenyoudonotspecifytheinstancevariable’sinitialvalue.

D:Localvariablesareautomaticallyinitialized.

答案:Everyinstancevariablehasadefaultinitialvalue—avalueprovidedbyJavawhenyoudonotspecifytheinstancevariable’sinitialvalue.

Whichofthefollowingstatementsisfalse?()

A:Theasterisk(*)injavac*.javaindicatesthatallfilesinthecurrentdirectoryendingwiththefilenameextension.javashouldbecompiled.

B:Alloftheabovearetrue.

C:Ifthedirectorycontainingtheappincludesonlyoneapp’sfiles,youcancompileallofitsclasseswiththecommandjavac*.java.

D:Thejavaccommandcancompilemultipleclassesatonce;simplylistthesource-codefilenamesafterthecommandwitheachfilenameseparatedbyacommafromthenext.

答案:Thejavaccommandcancompilemultipleclassesatonce;simplylistthesource-codefilenamesafterthecommandwitheachfilenameseparatedbyacommafromthenext.

Whichofthefollowingstatementsisfalse?()

A:IntheUML,eachclassismodeledinaclassdiagramasarectanglewiththreecompartments.Thetoponecontainstheclass’snamecenteredhorizontallyinboldface.Themiddleonecontainstheclass’sattributes,whichcorrespondtoinstancevariablesinJava.Thebottomonecontainstheclass’soperations,whichcorrespondtomethodsandconstructorsinJava.

B:PrivateattributesareprecededbythekeywordprivateintheUML.

C:TheUMLmodelsoperationsbylistingtheoperationnamefollowedbyasetofparentheses.Aplussign(+)infrontoftheoperationnameindicatesthattheoperationisapublic.

D:UMLrepresentsinstancevariablesasanattributename,followedbyacolonandthetype.

答案:PrivateattributesareprecededbythekeywordprivateintheUML.

Emptyparenthesesfollowingamethodnameinamethoddeclarationindicatethatthemethoddoesnotrequireanyparameterstoperformitstask.()

A:对B:错

答案:对Aprimitive-typevariablecanbeusedtoinvokeamethod.()

A:错B:对

答案:错Variablesdeclaredinthebodyofaparticularmethodareknownasinstancevariablesandcanbeusedinallmethodsoftheclass.()

A:错B:对

答案:错

第五章单元测试

Reference-typeinstancevariablesareinitializedbydefaulttothevaluenull.()

A:对B:错

答案:对Anyclassthatcontainspublicstaticvoidmain(String[]args)canbeusedtoexecuteanapp.()

A:对B:错

答案:对Whichofthefollowingstatementsisfalse?()

A:Everymethod’sbodyisdelimitedbyleftandrightbraces({and}).

B:Keywordnullindicatesthatamethodwillperformataskbutwillnotreturnanyinformation.

C:Variablesdeclaredinthebodyofaparticularmethodarelocalvariablesandcanbeusedonlyinthatmethod.

D:Amethod’sparametersarelocalvariablesofthemethod.

答案:Keywordnullindicatesthatamethodwillperformataskbutwillnotreturnanyinformation.

Whichofthefollowingstatementsisfalse?()

A:Emptyparenthesesfollowingamethodnameindicatethatthemethoddoesnotrequireanyparameterstoperformitstask.

B:Themethod’sreturntypespecifiesthetypeofdatareturnedtoamethod’scaller.

C:Whenamethodthatspecifiesareturntypeotherthanvoidiscalledandcompletesitstask,themethodmustreturnaresulttoitscallingmethod

D:Classesoftenprovidepublicmethodstoallowtheclass’sclientstosetorgetprivateinstancevariables;thenamesofthesemethodsmustbeginwithsetorget.

答案:Classesoftenprovidepublicmethodstoallowtheclass’sclientstosetorgetprivateinstancevariables;thenamesofthesemethodsmustbeginwithsetorget.

Whichofthefollowingstatementsisfalse?()

A:Tocallamethodofanobject,followtheobjectnamewithacomma,themethodnameandasetofparenthesescontainingthemethod’sarguments.

B:Scannermethodnextreadscharactersuntilanywhite-spacecharacterisencountered,thenreturnsthecharactersasaString.

C:Aclassinstancecreationexpressionbeginswithkeywordnewandcreatesanewobject.

D:Aconstructorissimilartoamethodbutiscalledimplicitlybythenewoperatortoinitializeanobject’sinstancevariablesatthetimetheobjectiscreated.

答案:Tocallamethodofanobject,followtheobjectnamewithacomma,themethodnameandasetofparenthesescontainingthemethod’sarguments.

Informationispassedtoamethodin________.()

A:themethodname

B:theargumentstothemethod

C:thatmethod’sreturn

D:themethodbody

答案:theargumentstothemethod

Awell-designedmethod________.()

A:repeatscodefoundinothermethods

B:performsmultipleunrelatedtasks

C:performsasingle,well-definedtask

D:containsthousandsoflinesofcode

答案:performsasingle,well-definedtask

Todeclareamethodasstatic,placethekeywordstaticbefore________inthemethod’sdeclaration.()

A:theargumentlist

B:themethodmodifier

C:thereturntype

D:themethodname

答案:thereturntype

WhichisacorrectstaticmethodcallofMathclassmethodsqrt?()

A:sqrt(900);

B:Mathmath=newMath();math.sqrt(900);

C:Math.sqrt(900);

D:math.sqrt(900);

答案:Math.sqrt(900);

WhichofthefollowingmethodsisnotintheMathclass?()

A:parseInt

B:abs

C:log

D:ceil

答案:parseInt

第六章单元测试

Mathstaticmethodrandomgeneratesarandomdoublevalueintherangefrom0.0()

A:uptobutnotincluding1.0

B:uptoandincluding100.0

C:uptobutnotincluding100.0

D:uptoandincluding1.0

答案:uptobutnotincluding1.0

Whichstatementcreatesarandomvaluefromthesequence2,5,8,11and14.SupposerandomNumbersisaSecureRandomobject.()

A:3+2*randomNumbers.nextInt(5);

B:2+5*randomNumbers.nextInt(3);

C:5+3*randomNumbers.nextInt(2);

D:2+3*randomNumbers.nextInt(5);

答案:2+3*randomNumbers.nextInt(5);

Asetofnamedconstantsthatstartwiththevalue0forthefirstconstantandincrementby1foreachsubsequentconstantcanbedeclaredasa(n)________.()

A:class

B:Noneoftheabove.

C:enumeration

D:enum

答案:enum

Arraysare________.()

A:variable-lengthentities

B:fixed-lengthentities

C:datastructuresthatcontainupto10relateddataitems

D:usedtodrawasequenceoflines,orrays

答案:fixed-lengthentities

TypesinJavaaredividedintotwocategories.Theprimitivetypesareboolean,byte,char,short,int,long,floatanddouble.Allothertypesare________types.()

A:reference

B:source

C:static

D:declared

答案:reference

Whichofthefollowingstatementsisfalse?()

A:Variablesoftypesbyte,short,int,long,floatanddoubleareinitializedto0.

B:Primitive-typeinstancevariablesareinitializedbydefault.

C:Variablesoftypebooleanareinitializedtotrue.

D:Aprimitive-typevariablecanstoreexactlyonevalueofitsdeclaredtypeatatime.

答案:Variablesoftypebooleanareinitializedtotrue.

Whichofthefollowingstatementsaboutarraysaretrue?

1:Anarrayisagroupofvariablescontainingvaluesthatallhavethesametype.

2:Elementsarelocatedbyindex.

3:Thelengthofanarraycisdeterminedbytheexpressionc.length();

4:Thezerothelementofarraycisspecifiedbyc[0].()

A:1,3,4

B:1,2,4

C:3,4

D:1,2,3,4

答案:1,2,4

Aprogrammermustdothefollowingbeforeusinganarray:()

A:declarethenreferencethearray.

B:createthenreferencethearray.

C:declarethencreatethearray.

D:createthendeclarethearray.

答案:declarethencreatethearray.

Considerthecodesegmentbelow.Whichofthefollowingstatementsisfalse?int[]g;g=newint[23];()

A:gisareferencetoanarrayofintegers.

B:Thefirststatementdeclaresanarrayreference.

C:Thevalueofg[3]is-1.

D:Thesecondstatementcreatesthearray.

答案:Thevalueofg[3]is-1.

Whichofthefollowingstatementsaboutcreatingarraysandinitializingtheirelementsisfalse?()

A:Whenanarrayiscreatedwithoperatornew,thenumberofelementsmustbeplacedinsquarebracketsfollowingthetypeofelementbeingstored.

B:Theelementsofanarrayofintegershaveavalueofnullbeforetheyareinitialized.

C:Thenewkeywordshouldbeusedtocreateanarray.

D:Aforloopiscommonlyusedtosetthevaluesoftheelementsofanarray.

答案:Theelementsofanarrayofintegershaveavalueofnullbeforetheyareinitialized.

Whichofthefollowinginitializerlistswouldcorrectlysettheelementsofarrayn?()

A:int[]n={1,2,3,4,5};

B:intn[5]={1;2;3;4;5};

C:arrayn[int]={1,2,3,4,5};

D:intn=newint(1,2,3,4,5);

答案:int[]n={1,2,3,4,5};

第七章单元测试

Whichofthefollowingstatementsisfalse?()

A:Asuperclassobjectisasubclassobject.

B:Javausesinterfacestoprovidethebenefitsofmultipleinheritance.

C:Asubclassisoftenlargerthanitssuperclass.

D:Theclassfollowingtheextendskeywordinaclassdeclarationisthedirectsuperclassoftheclassbeingdeclared.

答案:Asuperclassobjectisasubclassobject.

Inheritanceisalsoknownasthe()

A:is-arelationship.

B:uses-arelationship.

C:knows-arelationship.

D:has-arelationship.

答案:is-arelationship.

Whichofthefollowingisnotasuperclass/subclassrelationship?()

A:Noneoftheabove.

B:Employee/HourlyEmployee.

C:Sailboat/Tugboat.

D:Vehicle/Car.

答案:Sailboat/Tugboat.

Anadvantageofinheritanceisthat:()

A:Allmethodscanbeinherited.

B:Allinstancevariablescanbeuniformlyaccessedbysubclassesandsuperclasses.

C:Noneoftheabove.

D:Objectsofasubclasscanbetreatedlikeobjectsoftheirsuperclass.

答案:Objectsofasubclasscanbetreatedlikeobjectsoftheirsuperclass.

Whichofthefollowingkeywordsallowsasubclasstoaccessasuperclassmethodevenwhenthesubclasshasoverriddenthesuperclassmethod?()

A:super.

B:base.

C:public.

D:this.

答案:super.

Usingtheprotectedkeywordalsogivesamember:()

A:publicaccess.

B:privateaccess.

C:packageaccess.

D:blockscope.

答案:packageaccess.

Superclassmethodswiththislevelofaccesscannotbecalledfromsubclasses.()

A:public.

B:private.

C:protected.

D:package.

答案:private.

Whichofthefollowingstatementsisfalse?()

A:Aclass'sinstancevariablesarenormallydeclaredprivatetoenforcegoodsoftwareengineering.

B:It'softenmuchmoreefficienttocreateaclassbyinheritingfromasimilarclassthantocreatetheclassbywritingeverylineofcodethenewclassrequires.

C:AclasscandirectlyinheritfromclassObject.

D:Iftheclassyou'reinheritingfromdeclaresinstancevariablesasprivate,theinheritedclasscanaccessthoseinstancevariablesdirectly.

答案:Iftheclassyou'reinheritingfromdeclaresinstancevariablesasprivate,theinheritedclasscanaccessthoseinstancevariablesdirectly.

EveryclassinJava,except________,extendsanexistingclass.()

A:Object.

B:Integer.

C:Class.

D:String.

答案:Object.

Overridingamethoddiffersfromoverloadingamethodbecause:()

A:Overriddenmethodshavethesamesignature.

B:Neitheroftheabove.

C:Overloadedmethodshavethesamesignature.

D:Bothoftheabove.

答案:Overriddenmethodshavethesamesignature.

第八章单元测试

A(n)_____classcannotbeinstantiated.()

A:final.

B:abstract.

C:polymorphic.

D:concrete.

答案:abstract.

Non-abstractclassesarecalled________.()

A:implementableclasses.

B:realclasses.

C:concreteclasses.

D:instanceclasses.

答案:concreteclasses.

Ifthesuperclasscontainsonlyabstractmethoddeclarations,thesuperclassisusedfor________.()

A:Neither.

B:interfaceinheritance.

C:implementationinheritance.

D:Both.

答案:interfaceinheritance.

Whichofthefollowingcouldbeusedtodeclareabstractmethodmethod1inabstractclassClass1(method1returnsanintandtakesnoarguments)?()

A:publicintmethod1();

B:publicabstractintmethod1();

C:publicintnonfinalmethod1();

D:publicintabstractmethod1();

答案:public