java程序设计教程(第六版)课后习题答案

pp2.3

publicclassfudian{

publicstaticvoidmain(String[]args){

floata=2.10f,b=3.70f;

floatResult1,Result2,Result3;

Resultl=a+b;

Result2=a-b;

Result3=a*b;

System.out.println("Resultlis:"+Resultl);

System.out.println("Result2is:"+Result2);

System.out.println("Result3is:"+Result3);

)

)

2.4

publicclassTempConverter{

publicstaticvoidmain(String[]args){

finalintBASE=32;

finaldoubleCONVERSION_FACTOR=5.0/9.0;

doublecelsiusTemp;

intfahrenheitTemp=70;//valuetoconvert

celsiusTemp=(fahrenheitTemp

BASE)*CONVERSION_FACTOR;

System.out.printin("FahrenheitEquivalent:"+

fahrenheitTemp);

System.out.println("CelsiusTemperature:"+

celsiusTemp);

)

)

2.5

publicclassyinglizhuanqianmi{

publicstaticvoidmain(String[]args){

floatBase=1.60935f;

floatQianmi;

floatYingli=19.85f;

Qianmi=Yingli*Base;

System.out.println("YingLi:"+Yingli);

System.out.printin("QianMi:"+Qianmi);

)

)

2.6

publicclassTimeConverter1{

publicstaticvoidmain(String[]args){

intHour=5,Minute=35,Second=51;

intSECONDS;

SECONDS=Hour*60*60+Minute*60+Second;

System.out.printin(+Hour+"时"+Minute+"分"+Second+"秒");

System.out.println("换算成秒:"+SECONDS);

)

)

2.7

publicclassTimeConverter2{

publicstaticvoidmain(String[]args){

intSECONDS=10853;

intHour,Minute,Second;

Second=SECONDS%60;

Minute=(SECONDS-Second)%60;

Hour=(SECONDS-Second-Minute*60)/3600;

System.out.println(SECONDS+”秒，转化为)

System.out.println(Hour+"时"+Minute+"分"+Second+"秒)

)

)

2.9

importjava.util.*;

publicclassDollarbill{

publicstaticvoidmain(String[]args){

floatDollarl,Dollar2;

intTen,Five,One,Quarters,Dimes,Nickles,Pennies;

Scannerreader=newScanner(System.in);

System.out.println("输入币值：");

Dollarl=reader.nextFloat();

Dollar2=Dollarl*100;

Pennies=(int)Dollar2%5;

Nickles=((int)Dollar2%1O-Pennies)/5;

Dimes=((int)Dollar2-Pennies-Nickles*5)%50/10;

Quarters=(int)Dollar2%100/50;

One=((int)Dollar2-

Pennies-Nickles*5-Dimes*10-Quarters*50)%500/100;

Five=(int)Dollar2%1000/500;

Ten=(int)Dollar2/1000;

System.out.println(Ten+"tendollarbills");

System.out.println(Five+"fivedollarbills");

System.out.println(One+"onedollarbills");

System.out.println(Quarters+"quartersdollarbills");

System.out.println(Dimes+"dimesdollarbills");

System.out.println(Nickles+"nicklesdollarbills");

System.out.println(Pennies+"penniesdollarbills!");

2.11

importjava.util.*;

publicclassFenshuzhuanhuan{

publicstaticvoidmain(String[]args){

intx,y;

doubleResult=0;

Scannerreader=newScanner(System.in);

System.out.println("^Ax：");

x=reader.nextlnt();

System.out.println("输入y：");

y=reader.nextlnt();

Result+=x/y;

System.out.printin("分数"+x+'7"+y);

System.out.println("转换成小数是:"+Result);

}

)

2.16

importjavax.swing.JApplet;

importjava.awt.*;

publicclassOlympiclogoextendsJApplet{

publicvoidpaint(Graphicspage){

page.setColor(Color.blue);

page.drawOval(25,65,40,40);

page.setColor(Color.yellow);

page.drawOval(55,65,40,40);

page.setColor(Color.black);

page.drawOval(85,65,40,40);

page.setColor(Color.green);

page.drawOval(115,65,40,40);

page.setColor(Color.red);

page.drawOval(145,65,40,40);//circle

page.setColor(Color.cyan);

page.drawString("OLYMPICLOGO",40,30);

)

)

2.19

importjava.applet.*;

importjava.awt.*;

publicclassEx2_19extendsApplet{

publicvoidpaint(Graphicspage){

page.setColor(Color.BLACK);

page.setFont(newFont("楷体

",Font.ITALIC+Font.BOLD,30));

page.drawString("林少锋”,40,30);

page.setColor(Color.blue);

page.setFont(newFont("宋体",Font.BOLD,30));

page.drawString("林少锋"，70,80);

)

)

2.20

importjava.applet.*;

importjava.awt.*;

publicclassEx2_20extendsApplet{

publicvoidpaint(Graphicspage){

page.drawOval(35,35,130,130);

page.setColor(Color.red);

page.fillArc(35,35,130,130,0,45);

page.setColor(Color.blue);

page.fillArc(35,35,130,130,45,45);

page.setColor(Color.yellow);

page.fillArc(35,35,130,130,90,45);

page.setColor(Color.cyan);

page.fillArc(35,35,130,130,135,45)；

page.setColor(Color.gray);

page.fillArc(35,35,130,130,180,45);

page.setColor(Color.green);

page.fillArc(35,35,130,130,225,45)；

page.setColor(Color.darkGray);

page.fillArc(35,35,130,130,270,45);

page.setColor(Color,pink);

page.fillArc(35,35,130,130,315,45);

)

}

PP4.1

方法1

importjava.util.*;

publicclassCreateSphere{

/**

*@paramargs

*/

publicstaticvoidmain(String[]args){

//TODO自动生成方法存根

System.out.println("请输入直径d：");

Scannerscan=newScanner(System.in);

doubled=scan.nextDouble();

SphereD=newSphere(d);

D.Square();

D.Volum();

System.out.printin(D.toStringO);

)

publicclassSphere{

finaldoublePI=3.14;

doubleV,S;

doubled;

Sphere(doubled){

this.d=d;

publicvoidVolum(){

V=(4/3)*PI*(d/2)*(d/2)*(d/2);

publicvoidSquare(){

S=4*PI*(d/2)*(d/2);

)

publicStringtoString(){

Strings="";

Stringresultl=Double.toString(S);

Stringresult2=Double.toString(V);

s=("体积为："+result2+"面积为:"+resultl);

returns;

)

方法2

//Sphere.java

publicclassSphere{

privatedoublediameter;

publicSphere。{〃构造方法：无参数

this.diameter=1.0;

)

publicSphere(doubled){〃构造方法：带一个参数

this.diameter=d;

)

publicvoidsetDiameter(doubled){〃设置直径值的

方法

this.diameter=d;

)

publicdoublegetDiameter(){〃获取直径值的方法

returnthis.diameter;

)

publicdoublevolume。{〃计算球的体积

return

4*Math.PI*Math.pow(this.diameter/2,3)/3;

}

publicdoublearea。{〃计算球的表面积

return

4*Math.PI*Math.pow(this.diameter/2,2);

publicStringtoString(){

Stringout="该球体的直径为：〃+

this,diameter+"\n"+〃该球体的表面积为：〃+this.area()

+〃\n〃+

“该球体的体积为：〃+this.volume();

returnout;

)

)

//MultiSphere,java

importjava.util.Scanner;

publicclassMultiSphere

(

publicstaticvoidmain(String[]args){

Scannerscan=newScanner(System,in);

Spherespherel二newSphere();

Spheresphere2=newSphere(3.5);

System.out.printin(^spherel:〃+spherel

+〃\n〃);

System,out.println(，，sphere2:〃+sphere2

+〃\n〃);

System,out.printIn("spherel和sphere2分别

调用无参构造方法〃+

〃和带一个参数的构造方法进行初始化。〃)；

System.out.print("现在，请输入一"^数作为球

spherel的直径值：");

spherel.setDiameter(scan.nextDouble());

System,out.printIn("\n"+〃更改过的spherel:

“+spherel);

)

)

//////////////////////////////////////////////

////////////

PP4.2

方法1

importjava.util.Scanner;

publicclassCreateDog{

**

*@paramargs

publicstaticvoidmain(String[]args){

//TODO自动生成方法存根

System.out.print■工n("请输入狗的年龄age：");

Scannerscan=newScanner(System.in);

intage=scan.nextInt();

System.out.printIn("请输入狗的姓名name：");

Scannerscanl=newScanner(System.in);

Stringname=scanl.next();

KennelAGE=newKennel(age);

AGE.Age();

System.out.printIn(AGE.toString());

System.out.printin("狗的名字是："+name);

)

publicclassKennel{

finalintmul=7;

intage;

intagep;

charname;

Kennel(intage){

this.age=age;

=name;

publicvoidAge(){

agep=age*mul;

)

publicStringtoString(){

Strings="";

Stringrl=Integer.toString(age);

Stringr2=Integer.toString(agep);

s=（”狗的年龄为：”++”对应人的年龄为：”+r2）;

returns;

方法2

classDogl

(

Stringname;

intage;

publicDogl()

{

name="heizi";

age=l;

)

publicDogl(Stringnzinta

(

name=n;

age=a;

)

publicintDogAge(intAge)

intage=Age/7;

return(age);

publicvoidsetName(Stringnamel)

(

name=namel;

)

publicStringgetName()

(

return(name);

)

publicStringtoString()

(

Dogld=newDogl();

return("这只狗口可"+d.name+"已经有"+d.age+"岁

To")；

)

)

publicclassKennel{

publicstaticvoidmain(String[]args){

Dogldogl=newDogl();

System.out.printin("dogl的

name="+);

System.out.printIn("dogl的

age="+dogl.age);

Dogldog2=newDogl("xiaobai",2);

System.out.printIn("dog2的

name="+);

System.out.printIn("dog2的

age="+dog2.age);

dogl.setName("diandian");

dogl.getName();

System.out.printIn("dogl的

name=',+dogl.name);

intage=dogl.DogAge(35);

System.out.printIn("age="+age);

Stringr=dogl.toStringO;

System.out.printIn("r="+r);

)

)

//////////////////////////////////////////////

////////////

PP4.4

方法1

publicclassBook{

/**

*@paramargs

*/

publicstaticvoidmain(String[]args)

//TODO自动生成方法存根

Stringinfo=null;

Bookshelfbook;

BookshelfINFO=newBookshelf(info);

INFO.BOOK();

System.out.println(INFO.toString());

publicclassBookshelf{

Stringbookname;

Stringauthor;

Stringpublish;

Stringdate;

Stringbooks;

Stringinfo;

publicBookshelf(Stringinfo){

bookname="JAVA";

author="qwe";

publish="TsingHUA";

date="19890322";

=info;

)

publicStringBOOK(){

info=bookname+author+publish+date;

returninfo;

)

publicStringtoString(){

Stringbookinfo;

bookinfo="书名："+bookname+"作者：

"+author+"\n";

bookinfo+="出版社："+publish+""+"出版日期:

"+date;

returnbookinfo;

方法2

classBook

(

Stringtitle,authorrpublisherAcopyright;

Book()

{

title="JAVA编程语言设计，

author="JohnLewis;

publisher="电子工业出版社”；

copyright="xuesheng";

)

Book(Stringt,Stringa,StringprStringc)

(

title=t;

authored；

publisher=p;

copyright=c;

voidsetBook(String11,StringalfString

plzStringcl)

(

title=t1;

author=al;

publisher=pl;

copyrighted;

}

StringgetBookTitle()

{

return(title);

)

StringgetBookAuthor()

{

return(author);

)

StringgetBookPublisher()

{

return(publisher);

)

StringgetBookCopyright()

return(copyright);

}

publicStringtoString()

{

Bookbo=newBook();

return("这本名叫"+bo.书，作者是

"+bo.author+"出版社是"+bo.publisher+”版权归

"+bo.copyright+)；

)

}

publicclassBookshelf{

publicstaticvoidmain(String[]args){

Bookbook=newBook();

System.out.printIn(book.title+"

"+book.authors-""+book.publisher+"

"+book.copyright);//TODOAuto-generatedmethod

stub

Bookbookl=newBook("C语言程序设计"，”谭浩

强"，"清华出版社"，"zuozhe");

System.out.printin(bookl.title+"

"+bookl.author+""+bookl.publisher+"

"+bookl.copyright);

book.setBook("JAVA语言设计","William

Loftus西安电子出版社"，"sheng");

book..getBookTitle();

book.getBookAuthor();

book.getBookPublisher();

book.getBookCopyright();

System.out.printIn(book.title+"

"+book.author+n"+book.publisher+"

"+book.copyright);

Stringstr=book.toString();

System.out.print(nstr=n+str);

//////////////////////////////////////////////

////////////

PP4.5

classFlight{

Stringname,origin,destination;

intnumber;

publicFlight()

name="西安国际机场，

origin="西安”；

destination="m匕京

number=121;

)

publicFlight(Stringn,Stringo,Stringdrint

num)

(

name=n;origin=o;destination=d;number=num;

)

publicvoidsetFlight(Stringnl,String

olzStringdl,intnuml)

{

name=nl;

origin=ol;

destination=dl;

number=numl;

)

publicStringgetName()

returnname;

}

publicStringgetOrigin()

(

returnorigin;

}

publicStringgetDestination()

(

returndestination;

}

publiclonggetNumber()

(

returnnumber;

)

publicStringtoString()

(

Flightfl=newFlight();

return("这是"+f1.name+”的"+f1.number+”航

班，从"+f1.origin+"起飞至+f.destination+"降落。

")；

publicclassFlightTest{

publicstaticvoidmain(String[]args){

Flightflight=newFlight();

System.out.printIn("airline

Flight="+);

System.out.printIn(utheflight*s

origin=n+flight.origin);

System.out.printIn("destination

citys="+flight.destination);

System.out.printIn("flight

number="+flight.number);

Flightflightl=newFlight("天津航空天津

”西安”，321);

System.out.printin("airline

Flight="+);

System.out.printIn("theflight*s

origin=*'+flightl.origin);

System.out.printIn("destination

citys="+flight1.destination);

System.out.printIn("flight

number="+flightl.number);

flight.setFlight("北京航空北京"，"西安

M25);

flight.getName();

flight.getOrigin();

flight.getDestination();

flight.getNumber();

System.out.printIn("airline

Flight=n+);

System.out.printIn("theflight*s

origin=*'+flight.origin);

System.out.printin("destination

citys="+flight.destination);

System.out.printIn("flight

number="+flight.number);

Stringreal=flight.toString();

System.out.printIn(real);

)

)

//////////////////////////////////////////////

////////////

PP4.7

classPairOfDice{

privatefinalintMAX=6;

privateintfaceValue;

privateintfaceValuel;

publicPairOfDice()

{

faceValue=l;

faceValuel=2;

)

publicintroll()

(

faceValue=(int)(Math.random()*MAX)+1;

returnfaceValue;

)

publicintrolll()

(

faceValuel=(int)(Math.random()*MAX)+1;

returnfaceValuel;

)

publicvoidsetFaceValue(intvalue)

faceValue=value;

publicintgetFaceValue()

returnfaceValue;

)

publicvoidsetFaceValuel(intvalue)

(

faceValuel=value;

)

publicintgetFaceValuel()

(

returnfaceValuel;

)

publicintSum()

{

intsum=faceValue+faceValuel;

returnsum;

)

publicStringtoString()

(

Stringresult=Integer.t©String(faceValue);

returnresult;

publicclassRollingDice2{

publicstaticvoidmain(String[]args){

PairOfDicediel=newPairOfDice();

intfaceValue=diel.roll();

intfaceValuel=diel.roll1();

System.out.printIn("faceValue="+faceValue+n

faceValue1="+faceValuel);

intsum=diel.Sum();

System.out.printIn("sum="+sum);

PairOfDicedie2=newPairOfDice();

die2.setFaceValue(4);

intfaceValue2=die2.getFaceValue();

System.out.printIn("faceValue2="+faceValue2

)；

die2.setFaceValuel(3);

intfaceValue3=die2.getFaceValue1();

System.out.printIn(nfaceValue3=n+faceValue3

);

intsum2=die2.Sum();

System.out.printIn("sum2="+sum2);

)

)

App4.13源程序：

//PushDisplayPanel.java

importjava.awt.

importjava.awt.event.*;

importjavax.swing.*;

publicclassPushDisp1ayPane1extendsJPanel{

/**

*

*/

privatestaticfinallongserialVersionUID=

8617749572451960356L;

privateintcount;

privateJButtonpush;

privateJLabellabel;

intnum;

int1=100;

publicPushDisplayPanel()

]

push=newJButton("Pushit!");

push.addActionListener(newButtonListener());

label二newJLabel("Random:"+count);

add(push);

add(label);

setPreferredSize(newDimension(400,100));

setBackground(Color,pink);

}

privateclassButtonListenerimplements

ActionListener

(

publicvoidactionPerformed(ActionEventevent)

for(intj=0;j<I;j++){

num=(int)(Math,random()*100)+1;

label.setText("Random:"+num);

}

)

//Random,java

importjavax.swing.JFrame;

publicclassRandom{

publicstaticvoidmain(String[]args){

JFrameframe=newJFrame("Random");

frame.setDefaultCloseOperation(JFrame.EXIT0N_CL0SE)

frame.getContentPane().add(new

PushDisplayPanel());

frame,pack();

frame.setVisible(true);

///////////////////////////////////////////////////////

//////////////

App4.14源程序：

//AddPanel.java

importjava.awt.*;

importjava.awt.event.*;

importjavax.swing.*;

publicclassAddPanelextendsJPanel{

/**

*

*/

privatestaticfinallongserialVersionUID=

8617749572451960356L;

privateintcount;

privateJButtonpush,pushl;

privateJLabellabel;

intnum=50;

publicAddPanel()

(

push=newJButton("Add!〃);

pushl=newJButton("Minus!〃)；

push.addActionListener(newButtonListener());

pushl.addActionListener(newButtonListener());

label=newJLabel("Number:"+num);

add(push);

add(pushl);

add(label);

setPreferredSize(newDimension(400,100));

setBackground(Color,pink);

}

privateclassButtonListenerimplements

ActionListener

publicvoidactionPerformed(ActionEventevent)

if(event.getSource()-push)

num++;

else

num一

label.setText("Number:"+num);

}

//Number,java

importjavax.swing.JFrame;

publicclassNumber{

*©paramargs

publicstaticvoidmain(String[]args){

//TODO自动生成方法存根

JFrameframe=newJFrame("Random");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)

»

frame.getContentPane().add(newAddPanel());

frame,pack();

frame.setVisible(true);

}

)

///////////////////////////////////////////////////////

//////

补充：画一个转动的风车

importjava.awt.*;

importjava.awt.geom.*;

importjavax.swing.*;

publicclasstestarc

publicstaticvoidmain(String口args)

FillFrameframe=newFilIFrame();

frame.setDefaultCloseOperation(JFrame.EXITONCLOSE);

frame.setVisible(true);

classFilIFrameextendsJFrame

(

publicFilIFrame()

(

setTitle("FillTest");

setSize(400,400);

//addpaneltoframe

DrawPane1panel=newDrawPane1();

add(panel);

classDrawPanelextendsJPanelimplementsRunnable

privateThreadt;

privateintk=0;

publicDrawPane1(){

setBackground(Color,white);

t=newThread(this);

t.start();

)

publicvoidpaintComponent(Graphicsg)

(

super.paintComponent(g);

Graphics2Dg2=(Graphics2D)g;

doublexCenter=getWidth()/2;〃中心点x

doubleyCenter=getHeight()/2;〃中心点y

doubleradius=(int)(getWidth()*O.4);〃半径

Ellipse2Dcircle=new

Ellipse2D.Double(xCenter-radius,yCenter-radius,2*radius

,2*radius);

g2.draw(circle);

〃画一个风车

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

Arc2Darcl=new

Arc2D.Double(xCenter-radius,yCenter-radius,2*radius,2*r

adius,-30+90*i+30*k,30,Arc2D.PIE);

g2.setPaint(Color.RED);

g2.fill(arcl);

publicvoidrun()

(

for(inti=0;i<3;i=(i++)%3)

(

k=k=++k%3;

repaint();

try{

t.sleep(1000);

catch(Exceptione)

e.printStackTrace();

ApplO.K10.2源程序：

StringTooLon