全国计算机等级考试四级模拟试题四.docx

全国计算机等级考试四级模拟试题四.docx

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全国计算机等级考试四级模拟试题四

2019年全国计算机等级考试四级模拟试题（四）

　　（67）Howmanykeycomparisonsoccurinsearchingforkey35inthegivenhashtable?

（2分）

A）0B）1C）2D）3

（68）&Ifanewkey67isinsertedintothegivenhashtable,whatwillbeitsaddress?

（2分）

A）3B）4C）5D）6

（69）SupposethecontentsoftheDOSIF1.BATfileontheharddiskisasfollows.

@ECHOOFF

MEM>FILE1

SORTFILE2

DELFILE1

@DATE

@TIME

IFEXIST%1ECHO%IFFOUND

IfallofthecommandsaresuccessfullyexecutedafterIF1FILE1is

typed,thenthescreendisplays?

A）NoneB）DateandtimeC）FILE1ISFOUNDD）FILE2ISFOUND

（70）Ifthefilesinthecurrentdirectoryare

aac,abc,acb,acc,aca,ao,al,a2,ab,ac,aa,

andthecommandlsa?

[bc]isexecuted,howmanyfileswillbelisted?

（2分）

A）3B）4C）5D）6

（71）Inordertoappendastandardoutputtoanexistingfile,whichofthefollowingoperatorsisusedintheUNIXsystem?

A）|B）&C）>D）>>

（72）Considerthefollowingfigure,wheretheshadedpartsrepresentalreadyassignedblocksofmemory,andtheunshadedpartsrepresentfreeblocks.（2分）Ifthereisarequestfor40KBofmemoryandthebest-fitalgorithmisused,thenthebeginningaddressofmemorythatisallocatedinresponsetotherequestis

A）100KBB）190KBC）330KBD）410KB

（73）Onacertaindisk,thereare200tracks,numbered0-199,thecurrentpositionofthediskheadistrack53.Iftheshortest-seek-time-firstschedulingalgorithmisusedwhenthetracks

98,183,37,122,14,124,65,67

arerequested,thenthehead-movingsequencethatresultswillbe（2分）

A）65,67,37,14,98,122,124,183

B）65,67,37,98,122,124,183,14

C）65,67,98,122,124,183,37,14

D）98,183,37,122,14,124,65,67

（74）WhantoperationonrelationsRandSproducestherelationshownbelow?

{tuple│tuple∈Rtuple∈\S}

A）UnionB）DifferenceC）IntersectionD）Division

（75）WhenembeddingSQLinaClanguageprogram,theprefixthatshouldbeaddedtoallSQLstatementsinordertodistinguishSQLstatementsfromthehostlanguagestatementsis

A）：

B）EXECC）EXECSQLD）SQL

（76）IntheORACLEsystem,setsofSQLstatementsandcontrolflowstatementsthathavebeennamed,compiled,andstoredtnthedatabasearereferredtoasstored

A）batchesB）proceduresC）triggersD）transactions

（77）WhichofthefollowingstatementsaboutobjectorienteddatabasesisNOTcorrect?

（2分）

A）Eachobjecthasauniqueobjectidentityinthesystem.

B）Encapsulationandinheritancearetwoimportantfeaturesofobjectorienteddatabases.

C）Asubclasscaninherittheattributesandmethodsofallitssuperclasses.

D）Asuperclassincludestheattributesandmethodsofallitssubclasses.

（78）Inthedesignphaseofsoftwareengineering,decompositionoftheprogramintomodulesshouldfollowtheprinciplesof

A）lowcohesionwithlowcorplingB）lowcohesionwithhighcoupling

C）highcohesionwithlowcouplingD）highcohesionwithhighcoupling　　

（79）Specificationsforsoftwareshouldcontain severalcomponents,e.g.,specificationsof

informationflow,

userinterface,

functionalrequirements,and

designconstraints.

Twootherimportantcomponentsarespecificationsofthe（2分）

A）methodsoftestingandwaystoobtainqualityassurance

B）criteriafortestingandwaystoobtainqualityassurance

C）methodsoftestingandcriteriaforfunctionassurane

D）criteriafortestingandmethodsoffunctionassurance　　（80）Whichofthefollowingstatementsabouttestingsoftwarewithdatais（are）true?

I.Theprimarypurposeofsuchtestingistofinderrors.

II.Suchtestingcandemonstratetheexistenceoferrorsbutcannot

demonstratetheabsenceoferrors.

A）NeitherB）ⅠonlyC）ⅡonlyD）ⅠandⅡ

（81）Thetypeoftestingdoneduringsoftwareimplementationandbeforemoduleintegrationiscalled

A）unittestingB）betatesting

C）systemtestingD）acceptancetesting

（82）Whichofthefollowingis（are）trueaboutsoftwareportability?

I.Usingahigh-levellanguagethatconformstoanISOstandardguaranteesportabilityacrosstherangeofmachinesthatsupportthelanguage.

II.Portabilityisguaranteedacrossallmachinesthathavethesameinstructionsetandoperatingsystem.（2分）

A）NeitherB）ⅠonlyC）ⅡonlyD）ⅠandⅡ

（83）Amemory-memory,machineinstructionforacertainmachinehasthefollowingformat.

（Suchaninstructionissimilartoaregister-registerinstruction

exceptthattheoperandsaredisplacedaddressesinmemory.）

opcodememldispl1mem2displ2

Whichofthefollowingcouldbeanassemblylanuageinstructionthatwouldbetranslatedintoamemory-to-memoryinstructionforthismachine?

A）ADD10（R1）,20（R2）B）ADD（10R1）,（20R2）

C）ADDR1,10（R2）,20D）ADDR1,10,20（R2）

（84）Inacertaincachesystem,themodifiedcacheblockiswrittentomainmemoryonlywhentheblockisreplaced.AllofthefollowingareusedtodescribethispolicyEXCEPT

A）store-inB）write-backC）copy-backD）write-through

（85）Whenanamountofmemoryisrequestedthatislessthanthesizeofapage,butafullpageisallocated,theresultingwasteofmemoryiscalled

A）externalfragmentationB）internalfragmentation

C）inaccessiblepagefaultsD）inaccessiblegarbage

（86）ThetimethattheCPUspendsonagivenprogramcanbecomputedusingallofthefollowingexpressionsEXCEPT（2分）

A）（CPUclockcyclesfortheprogram）*（clockcycletime）

B）CPUclockcyclesfortheprogram

clockrate

C）（Instructioncount）*CPI

clockrate

D）（CPUclockcyclesfortheprogram）*CPI

clockrate

（87）ThemethodsusedinAsynchronousTransferMode（ATM）areswitchtechnologyandwhichofthefollowingisusedtodescribethismode?

A）cellexchangeB）packetexchange

C）messageexchangeD）informationexchange

（88）Inadatacommunicationsystem,thetransportmediawiththewidestfrequencybandandbestreliabilityisthe

A）telephonelineB）coaxialcable

C）radiochannelD）fiberopticcable

（89）WhichofthefollowingstatementsabouttheInternetis（are）true?

I.ItispossibletohavemultiplenamescorrespondingtothesameIPaddress.II.AllhostnamesmustberegisteredwithanInternet-widecentralregistry.

A）NeitherB）ⅠonlyC）ⅡonlyD）ⅠandⅡ

（90）AccordingtotheprincipleofCRCcalculation,givenaframe-bitseriesM=11100111andthemultiple-termformula,frame-bitseriesgeneratedbytheCRCG=110011,thentheCRCis（2分）

A）111101B）00011C）11010011D）1101001