面向?qū)ο蟮腃 程序設計第六版課后習題答案第十章

Chapter10

DEFININGCLASSESANDABSTRACTDATATYPES

1.SolutionsforandRemarksonSelectedProgrammingProblems

ThischaptercanbedoneafterChapter7,Arrays.However,Ihavenotusedanythingfrom

thatchapterinthesesolutions.Severalofthesesolutionscouldbesimplifiedingood

measureifarrayswereusedinsteadoftheextensiveswitchandnestedifelsestatements.

1.Classgradingprogram

Ihaveputstatementsofprogrammingstrategyandoftheproblemintheprogramcomments.

//chiOPrgl.cpp

#include<iostream>

usingnamespacestd;

constintCLASS_SIZE=5;

//Theproblemsaysthisisforaclass,ratherthanonestudent.One

//programmingstratagemistodealwithasinglestudent,thenextend

//totreatanarrayofNstudents.

//GradingProgram

//Policies:

//

//Twoquizzes,10pointseach

//midtermandfinalexam,100pointseach

//Ofgrade,finalcounts50%,midterm25%,quizes25%

//

//LetterGradeisassigned:

//90ormoreA

//80ormoreB

//70ormoreC

//60ormoreD

//lessthan60,F

1

Copyright?2007PearsonEducation,Inc.PublishingasPearsonAddison-Wesley

//

//Readastudent1sscores,

//outputrecord:scores+numericaverage+assignedlettergrade

//

//Useastructtocontainstudentrecord.

structStudentRecord

(

intstudentNumber;

doublequizl;

doublequiz2;

doublemidterm;

doublefinal;

doubleaverage;

chargrade;

)；

voidinput(StudentRecord&student);

//promptsforinputforonestudentfsetsthe

//structurevariablemembers.

voidcomputeGrade(StudentRecordsstudent);

//calculatesthenumericaverageandlettergrade.

voidoutput(constStudentRecordstudent);

//outputsthestudentrecord.

intmain()

(

StudentRecordstudent[CLASS_SIZE];

for(inti=0;i<CLASSESIZE;i++)

input(student[i]);

//EnclosingblockfixesVC++nfornloopcontroldefinedoutsideloop

{for(inti=0;i<CLASS_SIZE;i++)

computeGrade(student[i]);

output(student[i]);

cout<<endl;

}

}

return0;

)

voidinput(StudentRecord&student)

(

cout<<**enterthestudentnumber:n;

cin>>student.studentNumber;

cout<<student.studentNumber<<endl;

cout<<"entertwo10pointquizesM<<endl;

cin>>student.quizl>>student.quiz2;

cout<<student.quizl<<""<<student.quiz2<<endl;

cout<<"enterthemidtermandfinalexamgrades.n

<<"Theseare100pointtests\n',;

cin>>student.midterm>>student.final;

cout<<student.midterm<<""<<student.final

<<endl<<endl;

)

voidcomputeGrade(StudentRecord&student)

{

//Ofgrade,finalcounts50%,midterm25%,quizes25%

doublequizAvg=(student.quizl+student.quiz2)/2.0;

doublequizAvgNormalized=quizAvg*10;

student.average=student.final*0.5+

student.midterm*0.25+

quizAvgNormalized*0.25;

charletterGrade[]=,,FFFFFFDCBAAn;

intindex=static_cast<int>(student.average/10);

if(index<0||10<=index)

cout<<"Badnumericgradeencountered:"

<<student.average<<endl

<<"Aborting.\nn;

abort();

)

student.grade=letterGrade[index];

)

voidoutput(constStudentRecordstudent)

(

cout<<"Therecordforstudentnumber:"

<<student.studentNumber<<endl

<<"Thequizgradesare:“

<<student.quizl<<****<<student.quiz2

<<endl

<<"Themidtermandexamgradesare:"

<<student.midterm<<**"<<student.final

<<endl

<<"Thenumericaverageis:"<<student.average

<<endl

<<"andthelettergradeassignedis”

<<student.grade

<<endl;

)

Dataforthetestrun:

17109095

2989080

3787080

4585070

5404035

Commandlinecommandtoexecutethetextrun:

chlOprgl<data

Output:

enterthestudentnumber:1

entertwo10pointquizes

710

enterthemidtermandfinalexamgrades.Theseare100pointtests

9095

enterthestudentnumber:2

entertwo10pointquizes

98

enterthemidtermandfinalexamgrades.Theseare100pointtests

9080

enterthestudentnumber:3

entertwo10pointquizes

78

enterthemidtermandfinalexamgrades.Theseare100pointtests

7080

enterthestudentnumber:4

entertwo10pointquizes

58

enterthemidtermandfinalexamgrades.Theseare100pointtests

5070

enterthestudentnumber:5

entertwo10pointquizes

40

enterthemidtermandfinalexamgrades.Theseare100pointtests

4035

Therecordforstudentnumber:1

Thequizgradesare:710

Themidtermandexamgradesare:9095

Thenumericaverageis:91.25

andthelettergradeassignedisA

Therecordforstudentnumber:2

Thequizgradesare:98

Themidtermandexamgradesare:9080

Thenumericaverageis:83.75

andthelettergradeassignedisB

Therecordforstudentnumber:3

Thequizgradesare:78

Themidtermandexamgradesare:7080

Thenumericaverageis:76.25

andthelettergradeassignedisC

Therecordforstudentnumber:4

Thequizgradesare:58

Themidtermandexamgradesare:5070

Thenumericaverageis:63.75

andthelettergradeassignedisD

Therecordforstudentnumber:5

Thequizgradesare:40

Themidtermandexamgradesare:4035

Thenumericaverageis:32.5

andthelettergradeassignedisF

2.RedefineCDAccountfromDisplay10.1tobeaclassratherthanstruct.

Usethesamevariables,makethemprivate.

Addmemberfunctions:

toreturninitialbalance

toreturnbalanceatmaturity

toreturninterestrate

toreturntheterm

defaultconstructor

constructortosetspecifiedvalues

inputfunction(istream&);

outputfunction(ostream&);

Embedinatestprogram

ThecodeinDisplay10.1makesthebehavioroftherequiredfunctionsclear.

Noteoncapitalizationschemes:Iuseaslightlydifferentcapitalizationschemethanthe

author.Youshouldmakeyourconventionscleartothestudent.Anycapitalizationthat

producesreadablecodeisacceptabletothisauthor.Theinstructor,asalways,isleftfreeto

doasiswished.

//File:chlOPrg2.cpp

//Title:CDAccount

?include<iostream>

usingnamespacestd;

classCDAccount

(

public:

CDAccount();

CDAccount(doublebalzdoubleintRate,intT);

doubleInterestRate();

doubleInitialBalance();

doubleBalanceAtMaturity();

intTerm();

voidinput(istreamS);

voidoutput(ostream&);

private:

doublebalance;

doubleinterestRate;//inPERCENT

intterm;//monthstomaturity;

)；

intmain()

doublebalance;doubleintRate;

intterm;

CDAccountaccount=CDAccount(100.0,10.0f6);

cout<<"CDAccountinterestrate:"

<<account.InterestRate()<<endl;

cout<<°CDAccountinitialbalance:“

<<account.InitialBalance()<<endl;

cout<<"CDAccountbalanceatmaturityis:"

<<account.BalanceAtMaturity()?endl;

cout<<"CDAccounttermis:“<<account.Term()

<<”monthsendl;

account.output(cout);

cout<<"EnterCDinitialbalance,interestrate,

<<°andterm:“<<endl;

account.input(cin);

cout<<"CDAccountinterestrate:"

<<account.InterestRate()<<endl;

cout<<"CDAccountinitialbalance:"

<<account.InitialBalance()<<endl;

cout<<"CDAccountbalanceatmaturityis:"

<<account.BalanceAtMaturity()<<endl;

cout<<"CDAccounttermis:“<<account.Term()

<<"monthsn<<endl;

account.output(cout);

cout<<endl;

)

CDAccount::CDAccount(){/*donothing*/}

CDAccount::CDAccount(doublebal,doubleintRate,intT)

{

balance=bal;

interestRate=intRate;

term=T;

}

doubleCDAccount::InterestRate()

(

returninterestRate;

)

doubleCDAccount::InitialBalance()

(

returnbalance;

)

doubleCDAccount::BalanceAtMaturity()

(

returnbalance*(1+(interestRate/100)*(term/12.0));

}

intCDAccount::Term()

(

returnterm;

)

voidCDAccount::input(istream&inStream)

{

inStream>>balance;

inStream>>interestRate;

inStream>>term;

)

voidCDAccount::output(ostreamSoutStream)

(

outStream.setf(ios::fixed);

outStream.setf(ios::showpoint);

outStream.precision(2);

outStream<<"whenyourCDmaturesin”<<term

<<”monthsn<<endl

<<nitwillhaveabalanceof”

<<BalanceAtMaturity()<<endl;

)

★

Atypicalrunfollows:

CDAccountinterestrate:10

CDAccountinitialbalance:100

CDAccountbalanceatmaturityis:105

CDAccounttermis:6months

whenyourCDmaturesin6months

itwillhaveabalanceof105.00

EnterCDinitialbalance.interestrate,andterm:

200

10

12

CDAccountinterestrate:10.00

CDAccountinitialbalance:200.00

CDAccountbalanceatmaturityis:220.00

CDAccounttermis:12months

whenyourCDmaturesin12months

itwillhaveabalanceof220.00

*

3.CDaccount,differentinterface

RedothedefinitionofclassCDAccountfromProject2sothattheinterfaceisthesamebut

theimplementationisdifferent.Thenewimplementationissimilartothesecond

implementationofBankAccountinDisplay10.7.Herethebalanceisrecordedintwoint

values,onefbrdollars,oneforcents.Themembervariableforinterestratestoresthe

interestasafractionratherthanapercentage.TermisstoredasinProject2.

Remark:Thechangestobemadeareinthefunctionsthattakebalanceasargument.The

implementationofthemembersmustchange:

1)togeneratetheintobjectsdollarsandcentsfromtheexternalrepresentationofbalance

(adouble)

2)totakedollarsandcents(intobjects)fromtheinternalrepresentationandgeneratethe

externalinformation.

//File:chlOPrg3.cpp

//Title:CDAccount-modificationofProgrami,butwith

//differentimplementationbutSAMEinterface.

//ThenewimplementationshouldbesimilartoDisplay10.7

//recordbalanceastwointvalues:Onefordollars,onefor

//cents.interestrateisadouble(decimal)fractionrather

//thanapercent(0.043,not4.3%).termisstoredthesame

//wayasProgram1.

#include<iostream>

usingnamespacestd;

classCDAccount

public:

CDAccount();

CDAccount(doublebalzdoubleintRate,intT);

doubleInterestRate();

doubleInitialBalance();

doubleBalanceAtMaturity();

intTerm();

voidinput(istream&);

voidoutput(ostreamS);

private:

//doublebalance;

//doubleinterestRate;//inPERCENT

intdollars;

intcents;

doubleinterestRate;//decimalfraction:0.043ratherthan

4.3%

intterm;//monthstomaturity;

}；

CDAccount::CDAccount()

(

//donothing

}

CDAccount::CDAccount(doublebal,doubleintRate,intT)

(

dollars=int(bal);

cents=int(bal*100);

interestRate=intRate/100;

term=T;

)

doubleCDAccount::InterestRate()

returninterestRate*100;//internaldecimalfrac,

//external,percent

}

doubleCDAccount::InitialBalance()

(

returndollars+cents/100.00;

)

doubleCDAccount::BalanceAtMaturity()

{

return(dollars+cents/100.0)*

(1+(interestRate)*(term/12.0));

)

intCDAccount::Term()

(

returnterm;

)

voidCDAccount::input(istreamSinStream)

(

doubledBal;

inStream>>dBal;

dollars=int(dBal);

cents=int((dBal-dollars)*100);

inStream>>interestRate/100;

inStream>>term;

)

voidCDAccount::output(ostreamSoutStream)

outStream.setf(ios::fixed);

outStream.setf(ios::showpoint);

outStream.precision(2);

outStream<<“whenyourCDmaturesin”<<term

<<“monthsn<<endl

<<nitwillhaveabalanceof”

<<BalanceAtMaturity()<<endl;

}

intmain()

doublebalance;

doubleintRate;

intterm;

CDAccountaccount=CDAccount(100.0,10.0,6);

cout<<“CDAccountinterestrate:

<<account.InterestRate()<<endl;

cout<<“CDAccountinitialbalance:"

<<account.InitialBalance()<<endl;

cout<<”CDAccountbalanceatmaturityis:"

<<account.BalanceAtMaturity()<<endl;

cout<<“CDAccounttermis:“<<account.Term()

<<"monthsn<<endl;

account.output(cout);

cout<<"EnterCDinitialbalance,interestrate,”

<<”andterm:11?endl;

account.input(cin);

cout<<“CDAccountinterestrate:

<<account.InterestRate()<<endl;

cout<<“CDAccountinitialbalance:

<<account.InitialBalance()<<endl;

cout<<“CDAccountbalanceatmaturityis:"

<<account.BalanceAtMaturity()<<endl;

cout<<"CDAccounttermis:"<<account.Term()

<<”monthsn<<endl;

account.output(cout);

cout<<endl;

}

/*

Atypicalrunfollows:

CDAccountinterestrate:10

CDAccountinitialbalance:200

CDAccountbalanceatmaturityis:210

CDAccounttermis:6months

whenyourCDmaturesin6months

itwillhaveabalanceof210.00

EnterCDinitialbalance,interestrate,andterm:

200

10

12

CDAccountinterestrate:10.00

CDAccountinitialbalance:200.00

CDAccountbalanceatmaturityis:220.00

CDAccounttermis:12months

whenyourCDmaturesin12months

itwillhaveabalanceof220.00

*/

4.NoAnswerProvided

5.NoAnswerProvided

6.ClassMonth

Herewecreateanabstractdatatypetorepresentmonth.

Theclassmonthhasthefollowingmemberfunctions:

aconstructortosetmonthbasedonthefirst3lettersofthename

(uses3charargs)

aconstructortosetmonthbaseonmonthnumber,1=Januaryetc.

adefaultconstructor(whatdoesitdo?)

aninputfunctiontosetthemonthbasedonthemonthnumber

aninputfunctiontosetthemonthbasedonathree-characterinput

anoutputfunctionthatoutputsthemonthasaninteger,

anoutputfunctionthatoutputsthemonthastheletters,

afunctionthatreturnsthenextmonthasaMonthobject

NBeachinputandoutputfunctionhaveasingleformalparameterfor

thestream

Datastoreisanintobject.

Thisproblemdoesn'tsayanythingabouterrorchecking.Itiseasyand(Ihope)obvious

howtodoerrorchecking.Iwillrequiremystudentsputitin,andIuseithere.Thecareful

readerwillnotethattestingisnotthorough.Itisanexcellentexercisetoprovidetestdata

thatmakescoveragecomplete.(Completecoverageistotestallpossiblepathsthroughthe

program.)

Withthesecomments,hereisthecodeathesolutiontotheproblem:

//file:chl0prb5.cpp

//Title:Month

//TocreateandtestamonthADT

//Beginmonth.cppforProblem7HERE.

?include<fstream>//forfileandiostreamstuff

?include<cstdlib>//forexit()

#include<cctype>//fortolower()

classMonth

public:

Month(charclrcharc2,charc3);//done,debugged

//constructortosetmonthbasedonfirst

//3charsofthemonthname

Month(intmonthNumber);//done,debugged

//aconstructortosetmonthbaseonmonthnumberz

//I=Januaryetc.

Month();//done,nodebuggingtodo

//adefaultconstructor(whatdoesitdo?nothing)

voidgetMonthByNumber(istream&);//done,debugged

//aninputfunctiontosetthemonthbasedonthe

//monthnumber

voidgetMonthByName(istream&);//done,debugged

//inputfunctiontosetthemonthbasedonathree

//characterinput

voidoutputMonthNumber(ostreamS);//done,debugged

//anoutputfunctionthatoutputsthemonthasaninteger,

voidoutputMonthName(ostream&);//done,debugged

//anoutputfunctionthatoutputsthemonthastheletters.

MonthnextMonth();//

//afunctionthatreturnsthenextmonthasamonthobject

//NB:eachinputandoutputfunctionhaveasingleformal

//parameterforthestream.Thisaccessmemberaddedfor

//Problem7,notneededinProblem5

intmonthNumber();

private:

intmnth;

}；

//addedforProblem7.Notneedeinthisproblem

intMonth::monthNumber()

(

returnmnth;

)

MonthMonth::nextMonth()

(

intnextMonth=mnth+1;

if(nextMonth==13)

nextMonth=1;

returnMonth(nextMonth);

}

Month::Month(intmonthNumber)

(

mnth=monthNumber;

)

voidMonth::outputMonthNumber(ostream&in)

//cout<<"Thecurrentmonthis";//onlyfordebugging

cout<<mnth;

}

//Thisimplementationcouldprofitgreatlyfromuseof

//anarray.

voidMonth::outputMonthName(ostream&out)

(

//aswitchiscalledfor.Wedon*thaveoneyet.

if(1==mnth)out<<"Jan"；

elseif(2==mnth)out<<HFebn;

elseif(3==mnth)out<<"Mar11;

elseif(4==mnth)out<<“Apr”；

elseif(5==mnth)out<<“May”；

elseif(6==mnth)out<<nJunn;

elseif(7==mnth)out<<nJuln;

elseif(8==mnth)out<<HAugn;

elseif(9==mnth)out<<“Sep”；

elseif(10=：=mnth)out<<nOctn;

elseif(11=：=mnth)out<<“Nov”；

elseif(12=：=mnth)out<<nDecn;

)

voiderror(charcl,charc2fcharc3)

(

cout<<endl<<cl<<c2<<c3<<"isnotamonth.

Exiting\nn;

exit(1);

)

voiderror(intn)

cout<<endl<<n<<”isnotamonthnumber.Exiting"<<

endl;

exit(1);

}

voidMonth::getMonthByNumber(istream&in)

(

in>>mnth;//intMonth::mnth;

}

//useofanarrayandlinearsearchcouldhelpthis

//implementation.

voidMonth::getMonthByName(istream&in)

//Callserror(...)whichexits,ifthemonthnameiswrong.

//Anenhancementwouldbetoallowtheusertofixthis.

charclrc2,c3;

in>>cl>>c2>>c3;

cl=tolower(cl);//forcetolowercasesoanycase

c2=tolower(c2);//theuserentersisacceptable

c3=tolower(c3);

if(*j*==cl)

if(0==c2)

mnth=1;//jan

elseif(1u,==c2)

if(*n*==c3)

mnth=6;//jun

elseif(*11==c3)

mnth=7;//jul

elseerror(cl,c2,c3);//ju,notnor

elseerror(cl,c2zc3);//jrnotaoru

elseif(1f,==cl)

if(?==c2)

if(W==c3)

mnth=2;//feb

elseerror(cl,c2,c3);//fe,notb

elseerror(cl,c2,c3);//f,note

elseif(*m*==cl)

if(&==c2)

if(1y*==c3)

mnth=5;//may

elseif(1rf==c3)

mnth=3;//mar

elseerror(cl,c2,c3);//manota,r

elseerror(cl,c2zc3);//mnotaorr

elseif(*a*==cl)

if(*p*==c2)

if(1r,==c3)

mnth=4;//apr

elseerror(cl,c2,c3);//apnotr

elseif(1u1==c2)

if(*g*==c3)

mnth=8;//aug

elseerror(cl,c2zc3);//aunotg

elseerror(cl,c2zc3);//anotuorp

elseif('s'==cl)

if(9==c2)

if(P==c3)

mnth=9;//sep

elseerror(cl,c2,c3);//se,notp

elseerror(cl,c2,c3);//s,note

elseif(1o,==cl)

if(1c1==c2)

if(1f==c3)

mnth=10;//oct

elseerror(cl,c2zc3);//ocznott

elseerror(cl,c2zc3);//。，notc

elseif(*n1==cl)

if(。==c2)

if(*v1==c3)

mnth=11;//nov

elseerror(cl,c2,c3);//n。，notv

elseerror(cl,c2,c3);//n,noto

elseif(*d*==cl)

if(==c2)

if(*c1==c3)

mnth=12;//dec

elseerror(cl,c2,c3);//de,notc

elseerror(cl,c2,c3);//d,note

elseerror(clzc2,c3);//clnotjrf,m,a,s,o,n,ord

)

Month::Month(charclzcharc2zcharc3)

(

cl=tolower(cl);

c2=tolower(c2);

c3=tolower(c3);

if(1j1==cl)

if(0==c2)

mnth=l;//jan

elseif(1u1==c2)

if(1n1==c3)

mnth=6;//jun

elseif(111==c3)

mnth=7;//jul

elseerror(cl,c2,c3);//ju,notnor

elseerror(cl,c2,c3);//j,notaoru

elseif(*ff==cl)

if==c2)

if(fb1==c3)

mnth=2;//feb

elseerror(clzc2,c3);//fe,notb

elseerror(cl,c2,c3);//f,note

elseif(1==cl)

if(a==c2)

if(1y1==c3)

mnth=5;//may

elseif('r'==c3)

mnth=3;//mar

elseerror(cl,c2,c3);//manota,r

elseerror(cl,c2,c3);//mnotaorr

elseif(1a1==cl)

if(1p1==c2)

if(*r1==c3)

mnth=4;//apr

elseerror(cl,c2,c3);//apnotr

elseif(1u,==c2)

if(fgf==c3)

mnth=8;//aug

elseerror(cl,c2,c3);//aunotg

elseerror(cl,c2zc3);//anotuorp

elseif('s'==cl)

if(9==c2)

if(fp*==c3)

mnth=9;//sep

elseerror(cl,c2,c3);//se,notp

elseerror(cl,c2,c3);//s,note

elseif('o'==cl)

if('c'==c2)

if(ftf==c3)

mnth=10;//oct

elseerror(cl,c2,c3);//oc,nott

elseerror(cl,c2,c3);//oznotc

elseif(*n1==cl)

if(*of==c2)

if(1v,==c3)

mnth=11;//nov

elseerror(cl,c2,c3);//noznotv

elseerror(cl,c2,c3);//nznoto

elseif(*d1==cl)

if(*er==c2)

if(1c,==c3)

mnth=12;//dec

elseerror(cl,c2,c3);//de,notc

elseerror(cl,c2,c3);//d,note

elseerror(cl,c2,c3);//clnotj,f,m,a,s,o

//n,ord

)

Month::Month()

//bodydeliberatelyempty

}

//ENDmonth.cppforProblem7HERE.

intmain()

(

cout<<ntestingconstructorMonth(char,char,char)n<<

endl;

Monthm;

1

m=Month(*jz*a*,*n*);

m.outputMonthNumber(cout);cout<<"n;

m.outputMonthName(cout);cout<<endl;

1f

m=Month(*fze*,*b*);

m.outputMonthNumber(cout);cout<<”n;

m.outputMonthName(cout);cout<<endl;

1

m=Month(z*a*,r*);

m.outputMonthNumber(cout);cout<<”H;

m.outputMonthName(cout);cout<<endl;

1

m=Month(*aA*p*,*r*);

m.outputMonthNumber(cout);cout<<”H;

m.outputMonthName(cout);cout<<endl;

11

m=Month(*mA*a,*y*);

m.outputMonthNumber(cout);cout<<”H;

m.outputMonthName(cout);cout<<endl;

111

m=Month(*jz*uzn*);

m.outputMonthNumber(cout);cout<<”n;

m.outputMonthName(cout);cout<<endl;

11

m=Month(jz*u*,*1*);

m.outputMonthNumber(cout);cout<<"n;

m.outputMonthName(cout);cout<<endl;

11

m=Month(f*u*,g*);

m.outputMonthNumber(cout);cout<<”";

m.outputMonthName(cout);cout<<endl;

1f1

m=Month(sf*e,*p*);

m.outputMonthNumber(cout);cout<<”";

m.outputMonthName(cout);cout<<endl;

111

m=Month(or*c*z*t);

m.outputMonthNumber(cout);cout<<”";

m.outputMonthName(cout);cout<<endl;

1

m=Month(*nz*o*z*v*);

m.outputMonthNumber(cout