软件学院面向对象程序设计期末B卷.docx

软件学院面向对象程序设计期末B卷.docx

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软件学院面向对象程序设计期末B卷

一、选择题（30分）

说明：

每题2分，只有1个正确答案，请将正确答案填写在下面表格中。

题号

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

答案

1．WhichofthefollowingstatementsiscorrectaboutJavapackages?

A.Apackagemaycontainunlimitednumberofnestedsub-packages.

B.ApackageisacollectionofrelatedJavasourceprogram.

C.Usingtheimportstatementcanincludealltheclassesintothecurrentprogramfromaspecifiedpackageanditssub-packages.

D.Ifthereisnopackagestatementused,thecurrentclasswillnotbeinanypackage.

2．WhichoneisthewrongstatementaboutJavaconstructors?

A.Thenameofaconstructormustbethesameasitsclass’sname.

B.Aconstructorhasnoreturnvalueandcannotbemodifiedbyvoid.

C.Aconstructoroftheparentclasscannotbeinheritedbyitssub-classes.

D.Allconstructorsmustbemodifiedbypublic.

3．Givingthecodebellow:

classTest{

privateintm;

publicstaticvoidfun（）{/*somecode...*/}

}

Howtomakethemembervariablemaccessibleformethodfun（）?

A.change"privateintm"to"protectedintm"

B.change"privateintm"to"publicintm"

C.change"privateintm"to"staticintm"

D.change"privateintm"to"intm"

4．Whichofthefollowingfunctionsisanoverloadingfunctionof"publicvoidexample（）{...}"?

A.publicvoidexample（）{...}

B.publicintexample（）{...}

C.publicvoidexample2（）{...}

D.publicintexample（intm,floatf）{...}

5．InJava,aclassmayhavemanydifferentmethodswiththesamename.Thenumber,type,sequencesofargumentsinthesemethodsaredifferent,andthereturnvaluecanbedifferentaswell.Whatdowecallthisfeatureintermsofobject-orientedprogramming?

A.HidingB.Overriding

C.OverloadingD.ThisfeatureisnotsupportedinJava

6．Howtoexecutethefollowingprogram?

publicclassTest{

publicstaticvoidmain（Stringargs[]）{

System.out.println（args[0]）;

}

}

A.javaTest.classB.javaTest

C.javaTestaStringD.javacTest

7．Ifacontainerhasbeenresized,whichofthefollowinglayoutmanagerdidnotchangetheinternalcomponents'size?

A.CardLayoutB.FlowLayout

C.BorderLayoutD.GridLayout

8．Whichistherightstatementaboutexceptionhandling?

A.Injava,allexceptionsarenecessarytobecaughtandhandled.

B.The“catch”statementcatchesexceptionbytype-matching.

C.Inthe“try-catch-finally”structure,theprogramwillexitafterexceptionhandling.

D.Exceptionisakindoferrors,anditshouldbeabsolutelyavoidedinprograms.

9．Thefollowingstatementsareabouttype-casting,whichoneiscorrect?

A.Areferencevariableofaclasscanonlybeassignedtoanobjectofitsfirstlevelsub-classesofthisclass.

B.Anobjectcannotbecastedtothetypeofanotherclasswhichhasnoinheritancerelationshipwiththeobject’soriginalclass.

C.Achildclass’sreferencevariablecanbeassignedtoanobjectofitsparentclass.

D.Thereisonlyexplicitcasting,butnoimplicitcasting.

10．BothclassTeacherandStudentarethesub-classesofPerson.

Personp;Teachert;Students;//assumep,tandsarenotnull

if（tinstanceofPerson）{s=（Student）t;}

Whichstatementaboutthelastlineofexpressioniscorrect?

A.AnewStudentobjectwillbecreated.

B.Thetype-castingiscorrect.

C.Theexpressionisincorrect.

D.Thereisnosyntaxerrorbutwillgenerateruntimeerror.

11．Accordingtothecodebelow,whichstatementiscorrect?

publicclassTest{

staticObjecto;

publicstaticvoidmain（Stringargs[]）{

System.out.println（o）;

}

}

A.Generatescompileerror.

B.CompilesOK,buthasruntimeerrors.

C.Outputszero.

D.Outputs“null”.

12．Accordingtothecodebelow,selectthestatementwhichisfalse.

Strings="Hello";

Strings1=newString（"Hello"）;

Strings2=s1.intern（）;

Strings3="Hello";

A.s1==sB.s2==s

C.s==s3D.s2==s3

13．Thearraydefinitioncodeisgivenbelow,whichstatementiscorrect?

String[][]s=newString[10][];

A.Thedefinitionofarraysisillegalinsyntax.

B.sisa10×10two-dimensionalarray.

C.Allelementsinsare"".

D.sisanarrayoftenarrays.

14．Whichisthecorrectoutputaccordingtotheprogramgivenbellow?

publicstaticvoidmain（String[]args）{

Scannerscanner=newScanner（"thisisonethatistwo"）;

scanner.useDelimiter（"is"）;//thereisaspacebefore"is"

while（scanner.hasNext（））{

System.out.print（scanner.next（））;

}

}

A.thisonethattwoB.thonethattwo

C.thonethattwoD.thisisonethatistwo

15．Thefile“empty.txt”doesnotexistbefore,whatitscontentwillbeafterexecutingthefollowingcode.

publicstaticvoidmain（String[]args）throwsFileNotFoundException{

PrintWriterpr=newPrintWriter（newFile（"empty.txt"））;

pr.print（"one\ttwo"）;

pr.append（"\n1\t2"）;

pr.close（）;

}

A.onetwoB.one\ttwo

121\t2

C.one\ttwo\n1\t2D.onetwo12

二、改错题（20分）

说明：

写出每段代码的错误原因并改正错误，每小题4分，说明原因和改正各2分。

1．classFirst{}

importjava.io.*;

packagemypackage;

classSecond{}

2．classA{

Stringname;

publicA（Strings）{name=s;}

}

classBextendsA{

intid;

publicB（inti）{id=i;}

}

3．classAlpha{

privatevoidm（）{}

publicvoidp（）{}

}

classBetaextendsAlpha{

publicvoidm（）{}

privatevoidp（）{}

}

4．interfaceBase{

voidm（）;

voidn（）;

}

classChildimplementsBase{

publicvoidm（）{

System.out.println（"thisismethodm"）;

}

}

5．publicclassBextendsA{

finalvoidincrease（）{

value+=2;

}

}

classA{

intvalue=0;

finalvoidincrease（）{

value+=1;

}

}

三、程序阅读题（20分）

说明：

阅读下面程序并写出它们的输出结果，每小题5分。

1．Theprogramisasbelow:

classA{

inth=1;

publicA（inth）{

h=h;

System.out.println（this.h）;

this.h=h;

System.out.println（this.h）;

}

publicstaticvoidmain（String[]args）{

Aa=newA

（2）;

}

}

2．Theprogramisasbelow:

classBase{

publicBase（）{

System.out.println（"Whatapleasure!

"）;

}

publicBase（Strings）{

this（）;

System.out.println（"Iam"+s+"!

"）;

}

}

publicclassChildextendsBase{

publicstaticvoidmain（Stringargs[]）{

Childt=newChild（"Mike"）;

}

publicChild（Strings）{

super（s）;

System.out.println（"Howdoyoudo?

"）;

}

publicChild（）{

this（"IamTom"）;

}

}

3．Theprogramisasbelow:

classDivTest{

publicstaticvoidmain（String[]args）{

intr,n,d;

n=10;d=0;

try{

r=n/d;

System.out.println（"r="+r）;

}catch（ArithmeticExceptione）{

System.out.println（"Divide0exception!

"）;

}finally{

System.out.println（"Calculationcomplete!

"）;

}

System.out.println（"Programfinish!

"）;

}

}

4．Analyzetheprogrambellow,andexplainitseffect.

publicclassMyFrameextendsJFrame{

JButtonb1,b2;

publicMyFrame（）{

ActionListenera=newActionListener（）{

publicvoidactionPerformed（ActionEventevt）{

if（evt.getSource（）==b1）{

b1.setEnabled（false）;

b2.setEnabled（true）;

}else{

b1.setEnabled（true）;

b2.setEnabled（false）;

}

}

};

setLayout（newFlowLayout（））;

b1=newJButton（"1"）;b1.addActionListener（a）;add（b1）;

b2=newJButton（"2"）;b2.addActionListener（a）;add（b2）;

setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）;

setSize（150,100）;

setVisible（true）;

}

publicstaticvoidmain（String[]args）{

newMyFrame（）;

}

}

四、应用设计题（6分）

Thefollowingclassesareapartoftheclassesfoundedinacompany’spersonnelmanagementsystem,findouttheirrelationshipsandillustrateusingaUMLclassdiagram.

Employee,long-ternemployee,temporalemployee,manager,temporalsalesman.

五、程序设计题（24分）

说明：

按照题目要求编写下面两段程序。

1．Writeajavaapplicationprogramcontainingtheseclasses:

Person,Student,TestStudent.Thedetailsare:

⑴　ClassPerson

①　Properties

name:

String

sex:

char

id:

String

phone:

String

email:

String

②Methods

Person（Namename,charsex,Stringid）:

constructor

StringgetId（）

voidsetEmail（Stringemail）

voidsetPhone（Stringphone）

StringtoString（）:

outputsaperson’sinformation

⑵　ClassStudent

Asub-classderivedfromPerson,morepropertiesareadded:

①　Properties

sNo:

long

sClass:

String

②　Methods

Student（longsNo,Stringname,charsex,Stringid）:

constructor

setClass（StringsClass）

StringtoString（）:

outputsastudent’sinformation

⑶　ClassTestStudent

Aclassusedasthemainclasstotestthefunctions.

①　usethefollowinginformationtocreateastudentobject,aStudent.

Name:

GuoYang

Sex:

male

ID:

22033198807070333

sNo.:

2004002

②　setotherinformationtoaStudent.

E-mail:

yangguo@

Phone:

88078549

③　outputalltheinformationofaStudent.

2．Calculatethesumareaofcircles.（14points）

Therequirementsare:

⑴DefineaninterfaceShape,andano-argmethodgetArea（）thatreturnsdoublevalue.

⑵DefineaclassCircleimplementingtheShapeinterfaceabove,withintheclassthereisadoublepropertyradiusandtwoconstructors.Oneoftheconstructorshasnoargumentanditsetstheradiustozero;anotherconstructorsetstheradiusbyusingtheargumentprovided,orsetsradiustozerowhentheargumentislessthanzero.

⑶WriteaclassTestcontainingthemainmethodthatconvertseachcommand-lineargumenttodoublevalues,andcreateCircleobjectsaccordingtothedoublevaluesconverted.Exceptionhandlingshouldbeprovidedonconversingthecommand-linearguments.Ifanerroroccurred,printanerrormessageandcreatetheCircleusingthedefaultconstructor.Finally,calculateandoutputthesumareaofalltheCircles.