java程序设计(辛运帏-饶一梅-马素霞-第二版)课后习题答案

第二章

习题2.2

importjava.util.*;

classMyDate{

privateintyear;

privateintmonth;

privateintday;

publicMyDate(inty,intm,intd){〃构造函数，构造方法

year=y;

month=m;

day=d;

}//endpublicMyDate(inty,intm,intd)

publicintgetYear(){〃返回年

returnyear;

}//endgetYear()

publicintgetMonth。{〃返回月

returnmonth;

}//endgetMonth()

publicintgetDay。{〃返回日

returnday;

}//endgetDayO

}//endclassMyDate

classEmployee{

privateStringname;

privatedoublesalary;

privateMyDatehireDay;

publicEmployee(Stringn,doubles,MyDated){

name=n;

salary=s;

hireDay=d;

}//endpublicEmployee(Stringn,doubles,MyDated)

publicvoidprint(){

System.out.println("名字:“+name+”\n工资:"+salary+“\n雇佣年份:“+hireYear()+“\n");

}//endprint()

publicvoidraiseSalary(doublebyPercent){

salary*=l+byPercent/100;

}//end

publicinthireYear(){

returnhireDay.getYearQ;

}//endclassEmployee

publicclassMyTestClass{

publicstaticvoidmain(String[]args){

Employee[]staff=newEmployee[3];

staff[O]=newEmployee("HarryHacker",35000,newMyDate(1989,10,1));

staff[l]=newEmployee(nCarlCarcker",75000,newMyDate(1987,12,15));

staff[2]=newEmployee(uTonyTester',,38000,newMyDate(1990,3,12));

intintegerValue;

System.out.println("Theinformationofemployeeare:");

for(integerValue=0;integerValue<=2;integerValue++){

staff[integerValue].raiseSalary(5);

}//endfor()

for(integerValue=0;integerValue<=2;integerValue++){

staff[integerValue].print();

}//endfor()

}//endmain()

}//endclassMyTestClass

〃习题2.4

importjava.util.*;

publicclassDataType{

publicstaticvoidmain(String[]args){

booleanflag;

charyesChar;

bytefinByte;

intintValue;

longlongValue;

shortshortValue;

floatfloatValue;

doubledoubleValue;

flag=true;

yesChar=,y,;

finByte=30;

intValue=-7000;

longValue=2001;

shortValue=20000;

floatValue=9.997E-5f;

doubleValue=floatValue*floatValue;

System.out.println("thevaluesare:1');

System.out.println("布尔类型变量flag="+flag);

System.ouLprintln("字符型变量yesChar=H+yesChar);

System.out.println("字节型变量finByte="+finByte);

System.out.println("整型变量intValue=n+intValue);

System.out.println(“长整型变量longValue="+longValue);

System.out.println(“短整型变量shortValue=n+shortValue);

System.out.println("浮点型变量floatValue="+floatValue);

System.out.println("双精度浮点型变量doubleValue=H+doubleValue);

}//endmain()

)

〃习题2.9

importjava.util.*;

classPubTestl{

privateintivarl;

privatefloatfvarl,fvar2;

publicPubTestl(){

fvar2=0.0f;

)

publicfloatsum_f_I(){

fvar2=fvarl+ivar1;

returnfvar2;

)

publicvoidprint(){

System.out.println(,,fvar2=,,+fvar2);

)

publicvoidsetlvarl(intivalue){

ivarl=ivalue;

)

publicvoidsetFvarl(floativalue){

fvarl=ivalue;

)

)

publicclassPubMainTest{

publicstaticvoidmain(String[]args){

PubTestlpubtl=newPubTestl();

pubtl.setlvarl(lO);

publl.setFvar1(100.020;

pubtl.sum_f_I()；

publl.print();

)

)

〃习题2.10

importjava.util.*;

classDate{

privateintyear;

privateintmonth;

privateintday;

publicDate(intday,intmonth,intyear){〃构造函数，构造方法

this.year=year;

this.month=month;

this.day=day;

}//endpublicMyDate(inty,intm,intd)

publicintgetYear(){〃返回年

returnyear;

}//endgetYear()

publicintgetMonth(){〃返回月

returnmonth;

}//endgelMonth()

publicintgetDayO{〃返回日

returnday;

}//endgetDayO

}//endclassDate

publicclassTeacher{

Stringname;〃教师名字

booleansex;〃性别，true表示男性

Datebirth;〃出生日期

StringsalarylD;〃工资号

Stringdepart;〃教师所在系所

Stringposit;〃教师职称

StringgetName(){

returnname;

)

voidsetName(Stringname){

=name;

)

booleangetSex(){

returnsex;

)

voidsetSex(booleansex){

this.sex=sex;

)

DategetBirth(){

returnbirth;

)

voidsetBirth(Datebirth){

Ihis.biilh=birth;

StringgetSalaryID(){

returnsalaryID;

)

voidsetSalaiyID(StringsalarylD){

this.salarylD=salarylD;

)

StringgelDepart(){

returndepart;

)

voidsetDepart(Stringdepart){

this.depart=depart;

)

StringgetPosit(){

returnposit;

)

voidsetPosit(Stringposit){

this.posit=posit;

)

publicTeacher(){

System.out.println("父类无参数的构造方法!!!!!!!");

}//如果这里不加上这个无参数的构造方法将会出错!!!!

publicTeacher(Stringname,booleansex,Datebirth,

Stringsalaryid,Stringdepart,Stringposit){

=name;

this.sex=sex;

this上irth=birth;

this.salaryID=salaryid;

this.depart=depart;

this.posit=posit;

}//endTeacher()

publicvoidprint(){

System.out.printC'theteacher'name:n);

System.out.println(this.getNameO);

System.out.printC'theteacher'sex:'1);

if(this.getSex()==false){

System.out.println("女”);

)

else{

System.out.println("男");

)

System.out.printC'theteacherbirth:");

System.out.println(this.getBirth().getYear()+"-"+

this.getBirth().getMonth()+H-n+

this.getBirth().getDay());

System.out.print(Htheteacher'salaryid:");

System.out.println(this.getSalaryID());

System.out.print("theteacher'posit:n);

System.out.println(this.getPosit());

System.out.print(Htheteacher'depart:");

System.out.println(this.getDepart());

}//endprint()

publicstaticvoidmain(String[]args){

Datedtl=newDate(l1,23,1989);

Datedt2=newDate(2,6,1975);

Datedt3=newDate(l1,8,1964);

Datedt4=newDate(10,4,1975);

Datedt5=newDate(8,9,1969);

//创建各系教师实例，用来测试

Teachertl=newTeacher("王莹:false,dtl,”123",”经济学"Jprefessor”)；

ResearchTeacherrt=newResearchTeacher(“杨zi青”,true,dt2,“421"J软件工程，

"associateprefessor","software");

LabTeacherlat=newLabTeacher("王夏瑾,fa1se,dt3J163”,”外语北

"pinstrucor","speechlab");

LibTeacherlit=newLibTeacher("马二孩二日呢,出4,“521”,“大学物理”，

nprefessor"；'physicalLib");

AdminTeacherat=newAdminTeacher(“王xi”,false,dt5,“663“，“环境”，

,,prefessorn»,,dean");

〃〃〃〃/分别调用各自的输出方法，输出相应信息〃〃〃〃〃〃〃〃〃〃〃//〃〃

System.out.println(,'");

tl.print。;//普通教师信息

System.out.println(,'");

rt.print();〃研究系列教师信息

System.out.println(H");

lat.print();〃普通教师信息

System.out.println(H");

lit.print();〃实验系列教师信息

System.out.println(H");

at.print();〃行政系列教师信息

System.out.println(,'");

}//endmain()

}//endpublicclassTeacher

classResearchTeacherextendsTeacher{

privateStringresField;

publicResearchTeacher(Stringname,booleansex,Datebirth,Stringsalaryid,

Stringdepart,Stringposit,StringresField){

=name;

this.sex=sex;

this.birth=birth;

this.salarylD=salaryid;

this.depart=depart;

this.posit=posit;

this.resField=resField;

}//endpublicResearchTeacher(){)

StringgetResField(){

returnresField;

)

voidsetResField(StringresField){

this.resField=resField;

)

publicvoidprint(){

System.out.print(nresearchteacherinfois:");

System.out.print("theteacher'name:H);

System.out.println(this.getName());

System.out.print(ntheteacher'sex:");

if(this.getSex()==false){

System.out.println(H女");

}

else{

System.out.println("男");

)

Syslem.out.print("theteacher,birth:u);

System.out.println(this.getBirth().getYear()++

this.getBirth().getMonth()++

this.getBirth().getDay());

System.out.print("theteacher,salaryid:H);

System.out.println(this.getSalaryID());

System.out.print(ntheteachefposit:1');

System.out.println(this.getPosit());

System.out.print(Htheteacher'depart:");

System.out.println(this.getDepart());

System.out.print(HtheteachefresField:1');

System.out.println(this.getResField());

}//endprint()

}//endclassResearchTeacher

classLabTeacherextendsTeacher{

privateStringlabName;

publicLabTeacher(Stringname,booleansex,Datebirth,

Stringsalaryid,Stringdepart,

Stringposit,StringlabName){

=name;

this.sex=sex;

this.birth=birth;

this.salarylD=salaryid;

this.depart=depart;

this.posit=posit;

this.labName=labName;

}//endpublicResearchTeacher(){)

StringgetLabName(){

returnlabName;

)

voidsetLabName(StringlabName){

this.labName=labName;

)

publicvoidprint(){

System.out.print(nlabteacherinfois:");

System.out.print("theteacher'name:H);

System.out.println(this.getName());

System.out.print(ntheteacher'sex:");

if(this.getSex()==false){

System.out.println(H女");

}

else{

System.out.println("男");

)

Syslem.out.print("theteacher,birth:u);

System.out.println(this.getBirth().getYear()++

this.getBirth().getMonth()++

this.getBirth().getDay());

System.out.print("theteacher,salaryid:H);

System.out.println(this.getSalaryID());

System.out.print(ntheteachefposit:1');

System.out.println(this.getPosit());

System.out.print(Htheteacher'depart:");

System.out.println(this.getDepart());

System.out.print(Htheteacher!abName:;

System.out.println(this.labName);

}//endprint()

}//endclassLabTeacher

classLibTeacherextendsTeacher{

privateStringlibName;

publicLibTeacher(Stringname,booleansex,Datebirth,

Stringsalaryid,Stringdepart,

Stringposit,StringlibName){

=name;

this.sex=sex;

this.birth=birth;

this.salarylD=salaryid;

this.depart=depart;

this.posit=posit;

this.libName=libName;

}//endpublicResearchTeacher(){}

StringgetLibName(){

returnlibName;

)

voidsetLibName(StringlibName){

this.libName=libName;

)

publicvoidprint(){

System.out.print(nlibteacherinfois:");

System.out.print("theteacher'name:H);

System.out.println(this.getName());

System.out.print(ntheteacher'sex:");

if(this.getSex()==false){

System.out.println(H女");

}

else{

System.out.println("男");

)

Syslem.out.print("theteacher,birth:u);

System.out.println(this.getBirth().getYear()++

this.getBirth().getMonth()++

this.getBirth().getDay());

System.out.print("theteacher,salaryid:H);

System.out.println(this.getSalaryID());

System.out.print(ntheteachefposit:1');

System.out.println(this.getPosit());

System.out.print(Htheteacher'depart:");

System.out.println(this.getDepart());

System.out.print(Htheteacher!ibName:1');

System.out.println(this.libName);

}//endprint()

}//endclassLibTeacher

classAdminTeacherextendsTeacher{

privateStringmanagePos;

publicAdminTeacher(Stringname,booleansex,Datebirth,

Stringsalaryid,Stringdepart,

Stringposit,StringmanagePos){

=name;

this.sex=sex;

this.birth=birth;

this.salarylD=salaryid;

this.depart=depart;

this.posit=posit;

this.managePos=managePos;

}//endpublicResearchTeacher(){}

StringgetManagePos(){

returnmanagePos;

)

voidsetManagePos(StringmanagePos){

this.managePos=managePos;

)

publicvoidprint(){

System.out.print("adminteacherinfois:");

System.out.print(Htheteacher'name:1');

System.out.println(this.getName());

System.out.print(Htheteachefsex:'1);

if(this.getSex()==false){

System.out.println("女”);

)

else{

System.out.println(M男");

)

System.out.printC'theteachefbirth:");

System.out.println(this.getBirth().getYear()++

this.getBirth().getMonth()++

this.getBirth().getDay());

System.out.print(Htheteacher'salaryid:");

System.out.println(this.getSalaryID());

System.out.print("theteacher'posit:1');

System.out.println(this.getPositO);

System.out.print("theteacher'depart:");

System.out.println(this.getDepart());

System.out.print(ntheteacher'managePos:");

System.out.println(this.managePos);

}//endprint()

}//endclassAdminTeacher

习题2.11

publicclassCourse{

privateStringcourselD;

privateStringcourseName;

privateStringcourseType;

privateintclassHour;

privatefloatcredit;

publicCourse(StringcourselD,StringcourseName,StringcourseType,

intclassHour,floatcredit){

this.courseID=courseID;

this.courseName=courseName;

this.courseType=courseType;

this.classHour=classHour;

this.credit=credit;

}//endpublicCourse(){}

StringgetID(){

returncourselD;

)

voidsetID(Stringid){

this.courselD=id;

)

StringgetName(){

returncourseName;

)

voidsetName(Stringname){

this.courseName=name;

)

StringgetType(){

returncourseType;

)

voidsetType(Stringtype){

this.courseType=type;

)

intgetClassHour(){

returnclassHour;

)

voidsetClassHour(inthour){

this.classHour=hour;

)

floatgetCredit(){

returnclassHour;

)

voidsetCredit(floatcredit){

this.credit=credit;

)

publicvoidprint(){

System.out.printlnC'thebasicinfoofthiscourseasfollowed:'*);

System.out.println(,,courseID=',+this.getID());

System.out.println("courseName=n+this.getName());

System.out.println(McourseType=H+this.getType());

System.out.println(nclassHour="+this.getClassHour());

System.out.println(ncredit=H+this.getCredit());

)

publicstaticvoidmain(String[]args){

Coursecs=newCourse("dl2","java程序设计(第二版)","cs",64,3.0f);

System.out.println("")；

cs.print();

System.out.println("修改课程学分为4.0fH);

cs.setCredit(4);

cs.print();

)

)

〃习题2.12

publicclassMyGraphic{

StringlineColor;

StringfillColor;

MyGraphic(Slring1c,Stringfc){

this.lineColor=lc;

this.fillColor=fc;

)

voidprint(){

System.out.println(nlinecolorisn+this.lineColor+

"\tfillcoloris"+this.fillColor);

)

publicstaticvoidmain(String[]args){

floatrd=(float)4.5;

MyCirclemc=newMyCircle(rd,ublacku,"white'*);

MyRectanglemr=newMyRectangle(4,6,Mred","bluen);

System.out.printlnC'Circleinfo");

mc.print();

System.out.println(,,circumferenceis”+mc.calCircum());

System.out.println(nsquareis"+mc.calSquare());

System.out.println(Hrectangleinfo:");

mr.print();

System.out.println(ncircumferenceis"+mr.calCircum());

System.out.println(nsquareis"+mr.calSquare());

}//endmain(){}

}//endpublicclassMyGraphic

classMyRectangleextendsMyGraphic)

floatrLong;

floatrWidth;

MyRectangle(floatrefloatrw,String1c,Stringfc){

super(lc,fc);

this.rLong=rl;

this.rWidth=rw;

}//endMyRectangle(){}

floatcalCircum(){

return((float)((this.rLong+this.rWidth)*2));

)

floatcalSquare(){

return((float)(this.rLong*this.rWidth));

)

}//endclassMyRectangle

classMyCircleextendsMyGraphic{

floatradius;

MyCircle(floatrd,String1c,Stringfc){

super(lc,fc);

this.radius=rd;

}//endMyRectangle(){}

floatcalCircum(){

return(float)((this.radius*3.12*2));

)

floatcalSquare(){

return((float)(this.radius*this.radius*3.14));

)

}//endclassMyCircle

〃习题2.13

publicclassVehicle{

Stringbrand;

Stringcolor;

intprice;

intnumber;

publicVehicle(Stringb,Stringc){

this.brand=b;

this.color=c;

)

publicVehicle(Stringb,Stringc,intp,intn){

this(b,c);

this.price=p;

this.number=n;

)

voidprint(){

System.out.println(n\n");

System.out.println("thevehicleinfoasfollowed;

System.out.println(nbrand=n+this.brand+"\tM);

System.out.println(',color=,'+this.color+"\t");

System.out.printIn(Hprice="+this.price+n\t");

System.out.println(nnumber=u+this.number+n\tn);

}//endvoidprint()

publicstaticvoidmain(String[]args){

Vehiclecl=newVehicleC'vehiclel","white'*);

Vehiclec2=newVehicle(nvehicle?"；1whiten,300,1);

Carcr=newCar("carr,,"red",300,4,400);

Trucktk2=newTruck("truck1"/black",300,400);

cl.print();

c2.print();

cr.print();

tk2.print();

}//endmain()

}//endpublicclassVehicle

classCarextendsVehicle{

intspeed;

Car(Stringb,Stringc,intp,intn,ints){

super(b,c,p,n);

this.speed=s;

)

voidprint(){

super.printO;

System.out.print(nspeed="+this.speed);

)

}//endclassCar

classTruckextendsVehicle{

intspeed;

intweight;

Truck(Stringb,Stringc,ints,intw){

super(b,c);

this.speed=s;

this.weight=w;

)

voidprint(){

super.print();

System.out.print(nspeed="+this.speed);

System.out.print("weight="+this.weight);

)

}//endclassTruck

第三章

习题3.3

publicclassTest{

publicstaticvoidmain(String[]args){

intbl=l;

intb2=l;

System.out.println("bl=,'+bl);

Syslem.oul.prinlln(“b2="+b2);

bl«=31;

b2«=31;

System.out.println(nbl="+bl);

System.out.println(nb2=n+b2);

bl»=31;

System.out.println(Hbl=n+bl);

bl»=1;

System.out.println(“bl="+bl);

b2»>=31;

System.out.println("b2=M+b2);

b2»>=1;

System.out.println(,,b2=,'+b2);

)

)

〃习题34

publicclassFactorial{

privateintresult,inilVal;

publicstaticintFactorial(intn){

if(n==0){

return1;

)

returnn*Factorial(n-l);

)

publicvoidprint(){

System.out.println(initVal+"!=',+result);

}

publicvoidsetInitVal(intn){

initVal=n;

)

publicstaticvoidmain(String[]args){

Factorialff=newFactorial();

for(inti=0;i<=4;i++){

ff.setInitVal(2*(i+l));

ff.result=Factorial(ff.initVal);

ff.print();

}//endfor()

}//endmain()

}//endpublicclassFactorial

publicclassFactorial?{

privateintresult,initVal;

publicvoidprint(){

System.out.println(initVal+',!=,'+result);

)

publicvoidsetInitVal(intn){

initVal=n;

)

publicstaticvoidmain(String[]args){

Factorial2ff=newFactorial2();

for(inti=0;i<=4;i++){

ff.setInitVal(2*(i+1));

ff.result=l;

for(intj=2;j<=ff.initVal;j++){

ff.result*=j;

)

ff.print();

}//endfor()

}//endmain()

)

〃习题3.5

publicclassMathRandomTest{

publicstaticvoidmain(String[]args){

intcount=0,MAXofl00,MINofl00;

intnum,i;

MAXofl00=(int)(100*Math.random());

MINof100=(int)(100*Math.random());

System.out.print(MAXoflOO+"n);

System.out.print(MINofl00+"”);

if(MAXofl00>50)count++;

if(MINofl00>50)count++;

if(MAXofl00<MINof100)(

num=MINofl00;

MINofl00=MAXofl00;

MAXofl00=num;

}//endif()

for(i=0;i<98;i++){

num=(int)(lOO*Math.random。)；

System.out.print(num+((i+2)%10=9?',\n'|:M**));

if(num>MAXof100){

MAXofl00=num;

)

elseif(num<MINofl00){

MINofl00=num;

)

if(num>50){

count++;

)

)//endfor()

System.out.println(Hthemaxof100randomintegersisu+MAXofl00);

System.out.println(Htheminof100randomintegersisn+MINofl00);

System.out.println(nthenumberofrandommorethan50isM+count);

}//endmain()

}//endpublicclassMathRandomTest

〃习题3.7

publicclassPrintAst{

publicvoidprintAstar(){

System.out.print(n*");

)

publicvoidprintSpace(){

System.out.print(Hu);

)

publicstaticvoidmain(String[]args){

PrintAstpa=newPrintAst();

intinitNum=13;

for(inti=1;i<=initNum/2+1;i++){

fbr(intn=1;n<=i;n++){

pa.printSpace();

pa.printSpace();

)

for(intm=1;m<=initNum-2*i+2;m++){

pa.printSpaceO;

pa.printAstar();

)

System.out.printlnO;

}//endfor

if(initNum%2==0){

for(inti=1;i<=initNum/2;i++){

pa.printSpace();

pa.printSpaceO;

)

pa.printSpace();

pa.printAstar();

pa.printSpace();

pa.printAstar();

System.out.printlnO;

)

for(inti=initNum/2+2;i<=initNum;i++){

for(intn=1;n<=initNum-i+1;n++){

pa.printSpace();

pa.printSpace();

)

for(intm=1;m<=2*i-initNum;m++){

pa.printSpace();

pa.prinlAstar();

)

System.out.println();

}//endfor

System.out.printlnO;

}//endmain()

}//endpublicclassPrintAst

〃习题3.8

publicclassPrintTriag{

publicvoidprintAstar(){

System.out.print("*u);

)

publicstaticvoidmain(String[]args){

intinitLine=10;

intinitNum=10;

PrintTriagpt=newPrintTriagO;

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

for(intj=0;j<initNum-i;j++){

pt.printAstar();

)

System.out.printlnO;

)

}//endmain()

}//endpublicclassPrintTriag

习题3.9

importjava.util.*;

publicclassMultipleTable{

publicvoidprintFormula(inti,intj,intres){

System.out.print(i4-',*',+j+',=',+res4-nK);

}

publicstaticvoidmain(String[]args){

MultipleTablemt=newMultipleTable();

intinitNum=9;

intres=0;

for(inti=l；i<=initNum;i++){

fbr(intj=1;j<=i;j++){

res=i*j;

mt.printFormula(i,j,res);

)

System.out.printlnO;

}//endfor

}//endmain()

}//endpublicclassMultipleTable

习题3,10

importjava.io.*;

publicclassHuiWen{

booleanisHuiWen(charstr[],intn){

intnet=0;

inti,j;

for(i=0,j=n-1;i<n/2;i++,j--){

if(str[i]==strfj]){

net++;

}//endif

}//endfor

if(net=(int)(n/2)){

returntrue;

}//endif

else{

returnfalse;

)

}//endbooleanisHuiWen(charstr[],intn)

publicstaticvoidmain(String[]args){

HuiWenhwl=newHuiWen();

Stringpm="”；

try(

InputStreamReaderreader=newInputStreamReader(System.in);

BufferedReaderinput=newBuffercdReader(reader);

System.out.print(Hgiveyourteststring:\nH);

pm=input.readLine();

System.out.println(pm);

}//endtry

catch(lOExceptione){

System.out.print(e);

}//endcatch

booleanbw=hw1.isHuiWen(pm.toCharArray(),pm.length());

if(bw=true){

System.out.println("是回文”);

)

else{

System.out.println("不是回文)

}

}//endmain()

}//endpublicclassHuiWen

importjava.io.*;

publicclassHuiWen2{

Stringreverse(Stringwl){

Stringw2;

char[]strl=w1,toCharArray();

intlen=wl.length();

char[lstr2=newcharflen];

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

str2[i]=strl[len-l-i];

1

w2=newString(str2);

returnw2;

)

publicstaticvoidmain(String[]args){

HuiWen2hwl=newHuiWen2();

Stringpm=

try(

InputStreamReaderreader=newInputStreamReader(System.in);

BufferedReaderinput=newBufferedReader(reader);

System.out.printC^giveyourteststring:\nH);

pm=input.readLine();

}//endtry

catch(lOExceptione){

System.out.print(e);

}//endcatch

Stringw2=hw1.reverse(pm);

if(pareTo(pm)==0){

System.out.println("是回文)

)

else{

System.out.println("不是回文)

}

)

)

〃习题3.11

importjava.io.*;

publicclassPrimeNumber{

privateintpm;

publicvoidsetPm(intpm){

this.pm=pm;

)

publicbooleanisPrime(){

booleanbl=true;

inti=2;

for(i=2;i<=Math.sqrt(pm);){

if(pm%i==0){

bl=false;

break;

)

else{

i++;

)

}//endfor

returnbl;

}//endpublicbooleanisPrime()

publicstaticvoidmain(String[]args){

PrimeNumberprim=newPrimeNumber();

inttestNum=0;

try(

InputStreamReaderreader=newInputStreamReader(System.in);

BufferedReaderinput=newBufferedReader(reader);

System.out.print("giveyourtestnumber:\nu);

testNum=Integer.parseInt(input.readLine());

}//endtry

catch(IOExceptione){

System.out.println(e);

}//endcatch

prim.setPm(testNum);

booleanbl=prim.isPrime();

if(bl==true){

System.out.println(testNum+”是质数”);

)

else{

System.out.println(testNum+”不是质数”)；

)

}//endmain

}//endpublicclassPrimeNumber

习题3.12

importjava.io.*;

publicclassTempconverter{

doublecelsius(doubley){

return((y-32)/9*5);

)

publicstaticvoidmain(String[]args){

Tempconvertertc=newTempconverter();

doubletmp=0;

try(

InputStreamReaderreader=newInputStreamReader(System.in);

BufferedReaderinput=newBufferedReader(reader);

System.out.print(ngiveyourfahrenheitnumberAn");

tmp=Double.parseDouble(input.readLine());

}//endtry

catch(NumberFormatExceptione){

System.out.println(e);

}//endcatch

catch(IOExceptione){

System.out.println(e);

}//endcatch

System.out.printlnC'theCelsiusoftemperatureis,'+tc.celsius(tmp));

}//endmain()

}//endpublicclassTempconverter

习题3.13

importjava.io.*;

publicclassTrigsquare{

doublex,y,z;

Trigsquare(doublex,doubley,doublez){

this.x=x;

this.y=y;

this.z=z;

)

booleanisTriangle(){

booleanbl=false;

if(this.x>0&&this.y>0&&this.z>0){

if((this.x+this.y)>this.z&&(this.x+this.z)>this.y&&

(this.z+this.y)>this.x){

bl=true;

}//ebdif

else{

bl=false;

}//endelse

}//endif(this.x>0&&this.y>0&&this.z>0)

returnbl;

}//endbooleanisTriangle()

doublegetArea(){

doubles=(this.x+this.y+this.z)/2.0;

return(Math.sqrt(s*(s-this.x)*(s-this.y)*(s-this.z)));

}//enddoublegetArea()

publicstaticvoidmain(String[]args){

doubles[]=newdouble[3];

try(

InputStreamReaderreader