c语言程序设计现代方法第二版习题答案doc.docx
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c语言程序设计现代方法第二版习题答案doc
Chapter2
AnswerstoSelectedExercises
2.[was#2]（a）Theprogramcontainsonedirective（#include）andfourstatements（threecallsofprintfandonereturn）.
（b）
Parkinson'sLaw:
Workexpandssoastofillthetime
availableforitscompletion.
3.[was#4]
#include
intmain（void）
{
intheight=8,length=12,width=10,volume;
volume=height*length*width;
printf（"Dimensions:
%dx%dx%d\n",length,width,height）;
printf（"Volume（cubicinches）:
%d\n",volume）;
printf（"Dimensionalweight（pounds）:
%d\n",（volume+165）/166）;
return0;
}
4.[was#6]Here'sonepossibleprogram:
#include
intmain（void）
{
inti,j,k;
floatx,y,z;
printf（"Valueofi:
%d\n",i）;
printf（"Valueofj:
%d\n",j）;
printf（"Valueofk:
%d\n",k）;
printf（"Valueofx:
%g\n",x）;
printf（"Valueofy:
%g\n",y）;
printf（"Valueofz:
%g\n",z）;
return0;
}
WhencompiledusingGCCandthenexecuted,thisprogramproducedthefollowingoutput:
Valueofi:
5618848
Valueofj:
0
Valueofk:
6844404
Valueofx:
3.98979e-34
Valueofy:
9.59105e-39
Valueofz:
9.59105e-39
Thevaluesprinteddependonmanyfactors,sothechancethatyou'llgetexactlythesenumbersissmall.
5.[was#10]（a）isnotlegalbecause100_bottlesbeginswithadigit.
8.[was#12]Thereare14tokens:
a,=,（,3,*,q,-,p,*,p,）,/,3,and;.
AnswerstoSelectedProgrammingProjects
4.[was#8;modified]
#include
intmain（void）
{
floatoriginal_amount,amount_with_tax;
printf（"Enteranamount:
"）;
scanf（"%f",&original_amount）;
amount_with_tax=original_amount*1.05f;
printf（"Withtaxadded:
$%.2f\n",amount_with_tax）;
return0;
}
Theamount_with_taxvariableisunnecessary.Ifweremoveit,theprogramisslightlyshorter:
#include
intmain（void）
{
floatoriginal_amount;
printf（"Enteranamount:
"）;
scanf（"%f",&original_amount）;
printf（"Withtaxadded:
$%.2f\n",original_amount*1.05f）;
return0;
}
Chapter3
AnswerstoSelectedExercises
2.[was#2]
（a）printf（"%-8.1e",x）;
（b）printf（"%10.6e",x）;
（c）printf（"%-8.3f",x）;
（d）printf（"%6.0f",x）;
5.[was#8]Thevaluesofx,i,andywillbe12.3,45,and.6,respectively.
AnswerstoSelectedProgrammingProjects
1.[was#4;modified]
#include
intmain（void）
{
intmonth,day,year;
printf（"Enteradate（mm/dd/yyyy）:
"）;
scanf（"%d/%d/%d",&month,&day,&year）;
printf（"Youenteredthedate%d%.2d%.2d\n",year,month,day）;
return0;
}
3.[was#6;modified]
#include
intmain（void）
{
intprefix,group,publisher,item,check_digit;
printf（"EnterISBN:
"）;
scanf（"%d-%d-%d-%d-%d",&prefix,&group,&publisher,&item,&check_digit）;
printf（"GS1prefix:
%d\n",prefix）;
printf（"Groupidentifier:
%d\n",group）;
printf（"Publishercode:
%d\n",publisher）;
printf（"Itemnumber:
%d\n",item）;
printf（"Checkdigit:
%d\n",check_digit）;
/*Thefiveprintfcallscanbecombinedasfollows:
printf（"GS1prefix:
%d\nGroupidentifier:
%d\nPublishercode:
%d\nItemnumber:
%d\nCheckdigit:
%d\n",
prefix,group,publisher,item,check_digit）;
*/
return0;
}
Chapter4
AnswerstoSelectedExercises
2.[was#2]NotinC89.Supposethatiis9andjis7.Thevalueof（-i）/jcouldbeeither–1or–2,dependingontheimplementation.Ontheotherhand,thevalueof-（i/j）isalways–1,regardlessoftheimplementation.InC99,ontheotherhand,thevalueof（-i）/jmustbeequaltothevalueof-（i/j）.
9.[was#6]
（a）638
（b）321
（c）2-13
（d）000
13.[was#8]Theexpression++iisequivalentto（i+=1）.Thevalueofbothexpressionsisiaftertheincrementhasbeenperformed.
AnswerstoSelectedProgrammingProjects
2.[was#4]
#include
intmain（void）
{
intn;
printf（"Enterathree-digitnumber:
"）;
scanf（"%d",&n）;
printf（"Thereversalis:
%d%d%d\n",n%10,（n/10）%10,n/100）;
return0;
}
Chapter5
AnswerstoSelectedExercises
2.[was#2]
（a）1
（b）1
（c）1
（d）1
4.[was#4]（i>j）-（i6.[was#12]Yes,thestatementislegal.Whennisequalto5,itdoesnothing,since5isnotequalto–9.
10.[was#16]Theoutputis
onetwo
sincetherearenobreakstatementsafterthecases.
AnswerstoSelectedProgrammingProjects
2.[was#6]
#include
intmain（void）
{
inthours,minutes;
printf（"Entera24-hourtime:
"）;
scanf（"%d:
%d",&hours,&minutes）;
printf（"Equivalent12-hourtime:
"）;
if（hours==0）
printf（"12:
%.2dAM\n",minutes）;
elseif（hours<12）
printf（"%d:
%.2dAM\n",hours,minutes）;
elseif（hours==12）
printf（"%d:
%.2dPM\n",hours,minutes）;
else
printf（"%d:
%.2dPM\n",hours-12,minutes）;
return0;
}
4.[was#8;modified]
#include
intmain（void）
{
intspeed;
printf（"Enterawindspeedinknots:
"）;
scanf（"%d",&speed）;
if（speed<1）
printf（"Calm\n"）;
elseif（speed<=3）
printf（"Lightair\n"）;
elseif（speed<=27）
printf（"Breeze\n"）;
elseif（speed<=47）
printf（"Gale\n"）;
elseif（speed<=63）
printf（"Storm\n"）;
else
printf（"Hurricane\n"）;
return0;
}
6.[was#10]
#include
intmain（void）
{
intcheck_digit,d,i1,i2,i3,i4,i5,j1,j2,j3,j4,j5,
first_sum,second_sum,total;
printf（"Enterthefirst（single）digit:
"）;
scanf（"%1d",&d）;
printf（"Enterfirstgroupoffivedigits:
"）;
scanf（"%1d%1d%1d%1d%1d",&i1,&i2,&i3,&i4,&i5）;
printf（"Entersecondgroupoffivedigits:
"）;
scanf（"%1d%1d%1d%1d%1d",&j1,&j2,&j3,&j4,&j5）;
printf（"Enterthelast（single）digit:
"）;
scanf（"%1d",&check_digit）;
first_sum=d+i2+i4+j1+j3+j5;
second_sum=i1+i3+i5+j2+j4;
total=3*first_sum+second_sum;
if（check_digit==9-（（total-1）%10））
printf（"VALID\n"）;
else
printf（"NOTVALID\n"）;
return0;
}
10.[was#14]
#include
intmain（void）
{
intgrade;
printf（"Enternumericalgrade:
"）;
scanf（"%d",&grade）;
if（grade<0||grade>100）{
printf（"Illegalgrade\n"）;
return0;
}
switch（grade/10）{
case10:
case9:
printf（"Lettergrade:
A\n"）;
break;
case8:
printf（"Lettergrade:
B\n"）;
break;
case7:
printf（"Lettergrade:
C\n"）;
break;
case6:
printf（"Lettergrade:
D\n"）;
break;
case5:
case4:
case3:
case2:
case1:
case0:
printf（"Lettergrade:
F\n"）;
break;
}
return0;
}
Chapter6
AnswerstoSelectedExercises
4.[was#10]（c）isnotequivalentto（a）and（b）,becauseiisincrementedbeforetheloopbodyisexecuted.
10.[was#12]Considerthefollowingwhileloop:
while（…）{
…
continue;
…
}
Theequivalentcodeusinggotowouldhavethefollowingappearance:
while（…）{
…
gotoloop_end;
…
loop_end:
;/*nullstatement*/
}
12.[was#14]
for（d=2;d*d<=n;d++）
if（n%d==0）
break;
Theifstatementthatfollowstheloopwillneedtobemodifiedaswell:
if（d*d<=n）
printf（"%disdivisibleby%d\n",n,d）;
else
printf（"%disprime\n",n）;
14.[was#16]Theproblemisthesemicolonattheendofthefirstline.Ifweremoveit,thestatementisnowcorrect:
if（n%2==0）
printf（"niseven\n"）;
AnswerstoSelectedProgrammingProjects
2.[was#2]
#include
intmain（void）
{
intm,n,remainder;
printf（"Entertwointegers:
"）;
scanf（"%d%d",&m,&n）;
while（n!
=0）{
remainder=m%n;
m=n;
n=remainder;
}
printf（"Greatestcommondivisor:
%d\n",m）;
return0;
}
4.[was#4]
#include
intmain（void）
{
floatcommission,value;
printf（"Entervalueoftrade:
"）;
scanf（"%f",&value）;
while（value!
=0.0f）{
if（value<2500.00f）
commission=30.00f+.017f*value;
elseif（value<6250.00f）
commission=56.00f+.0066f*value;
elseif（value<20000.00f）
commission=76.00f+.0034f*value;
elseif（value<50000.00f）
commission=100.00f+.0022f*value;
elseif（value<500000.00f）
commission=155.00f+.0011f*value;
else
commission=255.00f+.0009f*value;
if（commission<39.00f）
commission=39.00f;
printf（"Commission:
$%.2f\n\n",commission）;
printf（"Entervalueoftrade:
"）;
scanf（"%f",&value）;
}
return0;
}
6.[was#6]
#include
intmain（void）
{
inti,n;
printf（"Enterlimitonmaximumsquare:
"）;
scanf（"%d",&n）;
for（i=2;i*i<=n;i+=2）
printf（"%d\n",i*i）;
return0;
}
8.[was#8]
#include
intmain（void）
{
inti,n,start_day;
printf（"Enternumberofdaysinmonth:
"）;
scanf（"%d",&n）;
printf（"Enterstartingdayoftheweek（1=Sun,7=Sat）:
"）;
scanf（"%d",&start_day）;
/*printanyleading"blankdates"*/
for（i=1;iprintf（""）;
/*nowprintthecalendar*/
for（i=1;i<=n;i++）{
printf（"%3d",i）;
if（（start_day+i-1）%7==0）
printf（"\n"）;
}
return0;
}
Chapter7
AnswerstoSelectedExercises
3.[was#4]（b）isnotlegal.
4.[was#6]（d）isillegal,sinceprintfrequiresastring,notacharacter,asitsfirstargument.
10.[was#14]unsignedint,becausethe（int）castappliesonlytoj,notj*k.
12.[was#16]Thevalueofiisconvertedtofloatandaddedtof,thentheresultisconvertedtodoubleandstoredind.
14.[was#18]No.Convertingftointwillfailifthevaluestoredinfexceedsthelargestvalueoftypeint.
AnswerstoSelectedProgrammingProjects
1.[was#2]shortintvaluesareusuallystoredin16bits,causingfailureat182.intandlongintvaluesareusuallystoredin32bits,withfailureoccurringat46341.
2.[was#8]
#include
intmain（void）
{
inti,n;
charch;
printf（"Thisprogramprintsatableofsquares.\n"）;
printf（"Enternumberofentriesintable:
"）;
scanf（"%d",&n）;
ch=getchar（）;
/*disposeofnew-linecharacterfollowingnumb
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