java大学实用教程(第三版)课后习题答案 43页

'习题解答第一章作业题1．publicclassHello{publicstaticvoidmain(Stringargs[]){System.out.pintln(“早上好，goodMorning”);}}2．importjava.applet.*;importjava.awt.*;publicclassBoyextendsApplet{publicvoidpaint(Graphicsg){g.setColor(Color.blue);g.drawString("你好,hello",12,30);}}第二章作业题1．publicclassZuoYe2_1{publicstaticvoidmain(Stringargs[]){charc="а";System.out.println("字母"+c+"在unicode表中的顺序位置:"+(int)c);System.out.println("字母表：");while(c<="я"){System.out.print(""+c);c=(char)(c+1);}}}2．importjava.util.*;publicclassZuoYe2_2{publicstaticvoidmain(Stringargs[]){Scannerreader=newScanner(System.in);longchengji=1;intm=0;while(reader.hasNextInt()){intx=reader.nextInt();m=m+1; chengji=chengji*x;}System.out.println(m+"个数的乘积为"+chengji);}}第三章作业题1．importjava.util.*;publicclassZuoYe3_1{publicstaticvoidmain(Stringargs[]){Scannerreader=newScanner(System.in);doubley=0,x=0;x=reader.nextDouble();if(x<0)y=-1+2*x;elseif(x==0)y=-1;elseif(x>0)y=-1+3*x;System.out.println(y);}}2．publicclassZuoYe3_2{publicstaticvoidmain(Stringargs[]){intsum=0,m=3,n=7,a=1;while(a<=1000){if(a%m==0&&a%n==0)sum=sum+a;a++;}System.out.println("sum="+sum);}}3．publicclassZuoYe3_3{publicstaticvoidmain(Stringargs[]){longsum=0,a=8,item=a,n=10,i=1;for(i=1;i<=n;i++){sum=sum+item;item=item*10+a; }System.out.println(sum);}}4．publicclassZuoYe3_4{publicstaticvoidmain(Stringargs[]){doublesum=0,a=1,b=1,fuhao=1,item=a/b;inti=1;while(i<=1000){sum=sum+fuhao*item;i++;fuhao=fuhao*(-1);b=b+2;item=a/b;}System.out.println("sum="+sum);}}5．publicclassZuoYe3_5{publicstaticvoidmain(Stringargs[]){doublesum=0,a=1;inti=1;while(i<=20){if(i>=10)sum=sum+a;i++;a=a*i;}System.out.println("sum="+sum);}}8．第四章作业题1． classDengCha{intstart,d;DengCha(){}DengCha(intstart,intd){this.start=start;this.d=d;}voidsetStart(ints){start=s;}voidsetD(intd){this.d=d;}intgetSum(intn){intsum=0,i=1;while(i<=n){sum=sum+start;start=start+d;i++;}returnsum;}}publicclassZuoYe4_1{publicstaticvoidmain(Stringargs[]){DengChashulie=newDengCha(2,3);System.out.println(shulie.getSum(100));shulie.setStart(10);shulie.setD(5);System.out.println(shulie.getSum(9));}}2．classLetter{publicvoidprintLetter(){for(charc="a";c<="z";c++)System.out.print(""+c);}}publicclassZuoYe4_2 {publicstaticvoidmain(Stringargs[]){Letterp=newLetter();p.printLetter();}}3．classSquareEquation{doublea,b;staticdoublec;doubleroot1,root2;booleanboo;publicSquareEquation(doublea,doubleb,doublec){this.a=a;this.b=b;SquareEquation.c=c;if(a!=0){boo=true;}else{boo=false;}}publicvoidgetRoots(){if(boo){System.out.println("是一元2次方程");doubledisk=b*b-4*a*c;if(disk>=0){root1=(-b+Math.sqrt(disk))/(2*a);root2=(-b-Math.sqrt(disk))/(2*a);System.out.printf("方程的根:%f,%fn",root1,root2);}else{System.out.printf("方程没有实根n");}}else{System.out.println("不是一元2次方程");}}publicvoidsetCoefficient(doublea,doubleb,doublec){this.a=a;this.b=b; SquareEquation.c=c;if(a!=0){boo=true;}else{boo=false;}}}publicclassZuoYe4_3{publicstaticvoidmain(Stringargs[]){SquareEquationequation1=newSquareEquation(4,5,1);SquareEquationequation2=newSquareEquation(3,5,-7);equation1.getRoots();equation2.getRoots();}}4．importjava.util.Scanner;classA{intf(intm,intn){if(m*n<0){System.out.println("有负数，程序退出");System.exit(0);}if(m=160||age<=0)thrownewIntegerException(age);//方法抛出异常，导致方法结束elsethis.age=age;}publicintgetAge(){System.out.println("年龄"+age+"合理");returnage;} }publicclassZuoYe6_5{publicstaticvoidmain(Stringargs[]){Peoplewang=newPeople(),zhang=newPeople();try{wang.setAge(189);System.out.println(wang.getAge());}catch(IntegerExceptione){System.out.println(e.toString());}try{zhang.setAge(28);System.out.println(zhang.getAge());}catch(IntegerExceptione){System.out.println(e.toString());}}}第六章作业题1．importjava.util.regex.*;importjava.util.*;publicclassZuoYe6_1{publicstaticvoidmain(Stringargs[]){Scannerreader=newScanner(System.in);Strings1=reader.nextLine();Patternp;Matcherm;p=Pattern.compile("[24680]A[13579]{2}");m=p.matcher(s1);while(m.find()){Stringstr=m.group();System.out.print("从"+m.start()+"到"+m.end()+"匹配模式子序列:");System.out.println(str);}}}2．importjava.util.regex.*;importjava.util.*;publicclassZuoYe4_1{publicstaticvoidmain(Stringargs[]){ Scannerreader=newScanner(System.in);Strings1=reader.nextLine();Patternp;Matcherm;p=Pattern.compile("\d+");m=p.matcher(s1);while(m.find()){Stringstr=m.group();System.out.print(str);}}}第七章作业题1．importjava.util.*;publicclassZuoYe7_2{publicstaticvoidmain(Stringargs[]){intyear,month;try{year=Integer.parseInt(args[0]);month=Integer.parseInt(args[1])+1;}catch(NumberFormatExceptione){year=2004;month=1;}System.out.println("日一二三四五六");Calendar日历=Calendar.getInstance();日历.set(year,month,1);int星期几=日历.get(Calendar.DAY_OF_WEEK)-1;Stringa[]=newString[星期几+31];for(inti=0;i<星期几;i++){a[i]="**";}for(inti=星期几,n=1;i<星期几+31;i++){if(n<=9)a[i]=String.valueOf(n)+"";else a[i]=String.valueOf(n);n++;}for(inti=0;iA=newHashSet(),B=newHashSet(),tempSet=newHashSet();A.add(newInteger(1));A.add(newInteger(2));A.add(newInteger(3));A.add(newInteger(4));B.add(newInteger(1));B.add(newInteger(3));B.add(newInteger(7));B.add(newInteger(9));B.add(newInteger(11));tempSet=(HashSet)A.clone();tempSet.retainAll(B);System.out.println("交：");Iteratoriter=tempSet.iterator();while(iter.hasNext()){Integerte=iter.next();System.out.printf("%d，",te.intValue());}tempSet=(HashSet)A.clone(); tempSet.addAll(B);iter=tempSet.iterator();System.out.println("并：");while(iter.hasNext()){Integerte=iter.next();System.out.printf("%d，",te.intValue());}tempSet=(HashSet)A.clone();tempSet.removeAll(B);System.out.println("差：");iter=tempSet.iterator();while(iter.hasNext()){Integerte=iter.next();System.out.printf("%d，",te.intValue());}}}5．importjava.util.*;classMyKeyimplementsComparable{doublenumber=0;MyKey(doublenumber){this.number=number;}publicintcompareTo(Objectb){MyKeyst=(MyKey)b;if((this.number-st.number)==0){return-1;}else{return(int)((this.number-st.number)*1000);}}}class硬盘{intsize;doubleprice;硬盘(intn,doublep){size=n;price=p;}}publicclassZuoYe4_1{publicstaticvoidmain(Stringargs[]){ int[]size={10,3,7,12,10,22,100,4,6,2};double[]price={1.2,9.56,2.4,9.3,16.77,12.66,7.4,5.5,5.6,8.9,1.9};硬盘[]s=new硬盘[10];for(inti=0;itreemap=newTreeMap();for(inti=0;icollection=treemap.values();Iterator<硬盘>iter=collection.iterator();while(iter.hasNext()){硬盘te=iter.next();System.out.println(te.size+","+te.price);}treemap.clear();for(inti=0;ilist=newLinkedList();ListcloneList=null;for(intk=1;k<=12;k++)list.add(newStudent("Iam"+k,k));try{FileOutputStreamfileOut=newFileOutputStream("a.txt");ObjectOutputStreamobjectOut=newObjectOutputStream(fileOut);objectOut.writeObject(list);FileInputStreamfileIn=newFileInputStream("a.txt");ObjectInputStreamobjectIn=newObjectInputStream(fileIn);cloneList=(List)objectIn.readObject();}catch(Exceptionevent){System.out.println(event);}Iteratoriter=cloneList.iterator();while(iter.hasNext()){Studentte=(Student)iter.next();System.out.println(te.number+","+te.name);}}} 6.importjava.io.*;publicclassZuoYe9_6{publicstaticvoidmain(Stringargs[]){Filef=newFile("Xiti12_6.java");try{RandomAccessFilerandom=newRandomAccessFile(f,"rw");random.seek(0);longm=random.length();while(m>=0){m=m-1;random.seek(m);intc=random.readByte();if(c<=255&&c>=0){System.out.print((char)c);}else{m=m-1;//一个汉字占2个字节random.seek(m);bytecc[]=newbyte[2];random.readFully(cc);System.out.print(newString(cc));}}random.close();}catch(IOExceptionee){}}}5.importjava.awt.*;importjava.awt.event.*;importjavax.swing.*;publicclassXiti8_5{publicstaticvoidmain(Stringargs[]){ComputerFramefr=newComputerFrame();fr.setTitle("计算"); }}classComputerFrameextendsJFrameimplementsActionListener{JTextFieldtext1,text2,text3;JButtonbutton1,button2,button3,button4;JLabellabel;publicComputerFrame(){setLayout(newFlowLayout());text1=newJTextField(10);text2=newJTextField(10);text3=newJTextField(10);label=newJLabel("",JLabel.CENTER);label.setBackground(Color.green);add(text1);add(label);add(text2);add(text3);button1=newJButton("加");button2=newJButton("减");button3=newJButton("乘");button4=newJButton("除");add(button1);add(button2);add(button3);add(button4);button1.addActionListener(this);button2.addActionListener(this);button3.addActionListener(this);button4.addActionListener(this);setSize(400,320);setVisible(true);setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);validate();}publicvoidactionPerformed(ActionEvente){doublen;if(e.getSource()==button1){doublen1,n2;try{n1=Double.parseDouble(text1.getText());n2=Double.parseDouble(text2.getText());n=n1+n2;text3.setText(String.valueOf(n));label.setText("+");} catch(NumberFormatExceptionee){text3.setText("请输入数字字符");}}elseif(e.getSource()==button2){doublen1,n2;try{n1=Double.parseDouble(text1.getText());n2=Double.parseDouble(text2.getText());n=n1-n2;text3.setText(String.valueOf(n));label.setText("-");}catch(NumberFormatExceptionee){text3.setText("请输入数字字符");}}elseif(e.getSource()==button3){doublen1,n2;try{n1=Double.parseDouble(text1.getText());n2=Double.parseDouble(text2.getText());n=n1*n2;text3.setText(String.valueOf(n));label.setText("*");}catch(NumberFormatExceptionee){text3.setText("请输入数字字符");}}elseif(e.getSource()==button4){doublen1,n2;try{n1=Double.parseDouble(text1.getText());n2=Double.parseDouble(text2.getText());n=n1/n2;text3.setText(String.valueOf(n));label.setText("/");}catch(NumberFormatExceptionee){text3.setText("请输入数字字符");}}validate();}}6. importjava.awt.*;importjava.awt.event.*;importjavax.swing.*;publicclassXiti8_6{publicstaticvoidmain(Stringargs[]){newWindowPanel();}}classMypanelextendsJPanelimplementsActionListener{JButtonbutton;JTextFieldtext;Mypanel(){button=newJButton("");text=newJTextField(12);add(button);add(text);button.addActionListener(this);}publicvoidactionPerformed(ActionEvente){Stringname=text.getText();if(name.length()>0)button.setText(name);validate();}}classWindowPanelextendsJFrame{Mypanelpanel1,panel2;WindowPanel(){panel1=newMypanel();panel2=newMypanel();panel1.setBackground(Color.red);panel2.setBackground(Color.blue);add(panel1,BorderLayout.SOUTH);add(panel2,BorderLayout.NORTH);setSize(300,320);setVisible(true);validate();setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);}}7．importjava.awt.*;importjava.awt.event.*;importjavax.swing.*; publicclassXiti8_7{publicstaticvoidmain(Stringargs[]){newWindowColor();}}classWindowColorextendsJFrame{JButtonbutton;JTextFieldtext;JComboBoxlist;WindowColor(){setLayout(newFlowLayout());button=newJButton("hello");button.setBackground(Color.pink);button.setForeground(newColor(12,26,200));text=newJTextField("howareyou");text.setBackground(Color.yellow);text.setForeground(newColor(200,26,20));list=newJComboBox();list.addItem("Hello");list.addItem("Java");list.setBackground(Color.cyan);list.setForeground(newColor(100,100,100));add(list);add(button);add(text);setSize(300,320);setVisible(true);validate();setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);}}8．importjava.awt.*;importjava.awt.event.*;importjavax.swing.*;publicclassXiti8_8{publicstaticvoidmain(Stringargs[]){MoveFramef=newMoveFrame();f.setBounds(12,12,300,300);f.setVisible(true);f.setTitle("移动");f.validate();f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);} }classMoveFrameextendsJFrameimplementsActionListener{JButtoncontrolButton,movedButton;publicMoveFrame(){controlButton=newJButton("单击我运动另一个按钮");controlButton.addActionListener(this);movedButton=newJButton();movedButton.setBackground(newColor(12,200,34));setLayout(null);add(controlButton);add(movedButton);controlButton.setBounds(10,30,180,30);movedButton.setBounds(100,100,20,20);}publicvoidactionPerformed(ActionEvente){intx=movedButton.getBounds().x;inty=movedButton.getBounds().y;x=x+5;y=y+1;movedButton.setLocation(x,y);if(x>200){x=100;y=100;}}}9.importjava.awt.*;importjava.awt.event.*;importjavax.swing.*;publicclassE{publicstaticvoidmain(Stringargs[]){JFramefr=newJFrame();fr.add(newLP(),BorderLayout.CENTER);fr.setVisible(true);fr.setBounds(12,12,300,300);fr.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);fr.validate();}}classLPextendsJLayeredPaneimplementsMouseListener,MouseMotionListener{JButtonbutton[];JTextFieldtext[]; intx,y,a,b,x0,y0;LP(){setLayout(newFlowLayout());button=newJButton[8];for(intk=0;k=300)y=300;}elseif(e.getKeyCode()==KeyEvent.VK_LEFT){x=x-moveDistance;com.setLocation(x,y);RectanglecomRect=com.getBounds();for(intk=0;k=300)x=300;}}publicvoidkeyTyped(KeyEvente){}publicvoidkeyReleased(KeyEvente){}}第十章作业题1．importjava.awt.*;importjava.awt.event.*;importjavax.swing.*;publicclassZuoYe10_1{publicstaticvoidmain(Stringargs[]){MathWindowwin=newMathWindow();}}classMathWindowextendsJFrame{JTextFieldinputText;JButtonbutton;MathWindow(){inputText=newJTextField(10);button=newJButton("hello");button.addActionListener(newActionListener(){publicvoidactionPerformed(ActionEvente){inputText.setText(button.getText());}});setLayout(newFlowLayout());add(inputText);add(button);setBounds(100,100,260,190); setVisible(true);validate();setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);}}2.importjava.awt.*;importjava.awt.event.*;importjavax.swing.*;publicclassZuoYe10_2{publicstaticvoidmain(Stringargs[]){MathWindowwin=newMathWindow();}}classMathWindowextendsJFrameimplementsActionListener{JTextFieldinputText,showUnicode;JButtonbutton;MathWindow(){inputText=newJTextField(10);showUnicode=newJTextField(10);button=newJButton("enter");button.addActionListener(this);inputText.addActionListener(this);setLayout(newFlowLayout());add(inputText);add(button);add(showUnicode);setBounds(100,100,260,190);setVisible(true);validate();setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);}publicvoidactionPerformed(ActionEvente){Strings=inputText.getText();StringBufferstr=newStringBuffer();for(inti=0;i=300)y=300;}elseif(e.getKeyCode()==KeyEvent.VK_LEFT){x=x-moveDistance;com.setLocation(x,y);RectanglecomRect=com.getBounds();for(intk=0;k=300)x=300;}} publicvoidkeyTyped(KeyEvente){}publicvoidkeyReleased(KeyEvente){}}8.importjava.awt.event.*;importjava.awt.*;importjavax.swing.*;importjava.io.*;publicclassZuoYe10_8{publicstaticvoidmain(Stringargs[]){newDwindow();}}classDwindowextendsJFrameimplementsActionListener{JTextFieldinputNumber;JTextAreashow;Dwindow(){inputNumber=newJTextField(22);inputNumber.addActionListener(this);show=newJTextArea();add(inputNumber,BorderLayout.NORTH);add(show,BorderLayout.CENTER);setBounds(60,60,300,300);setVisible(true);validate();setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);}publicvoidactionPerformed(ActionEvente){booleanboo=false;if(e.getSource()==inputNumber){Strings=inputNumber.getText();for(inti=0;i=1000){intn=JOptionPane.showConfirmDialog(this,"确认保存该数字到文件？","确认对话框",JOptionPane.YES_NO_OPTION);if(n==JOptionPane.YES_OPTION){saveNumber(number);}elseif(n==JOptionPane.NO_OPTION){inputNumber.setText(null);}}elsesaveNumber(number);}}}voidsaveNumber(intn){RandomAccessFileout=null;try{out=newRandomAccessFile("a.dat","rw");out.seek(out.length());out.writeUTF("integer：");out.writeInt(n);out.close();}catch(Exceptione){}}}第十一章作业题1．参考例子11-2和11-32．参考例子11-6第十二章作业题1．参考例子12-12．参考例子12-2 3．参考例子12-34．使参考例子12-4。5．使参考例子12-8第十三章作业题1．importjava.applet.*;importjava.awt.*;importjava.awt.event.*;publicclassZuoYe13_1extendsAppletimplementsActionListener{TextFieldtext1,text2,text3;PoliceManpolice;publicvoidinit(){text1=newTextField(10);text2=newTextField(10);text3=newTextField(10);police=newPoliceMan(this);add(text1);add(text2);add(text3);text1.addActionListener(this);text1.addActionListener(police);}publicvoidactionPerformed(ActionEvente){Stringnumber=e.getActionCommand();intn=Integer.parseInt(number);intm=n*n;text2.setText(n+"的平方是:"+m);}}classPoliceManimplementsActionListener{Example9_3a=null;PoliceMan(Example9_3a){this.a=a;}publicvoidactionPerformed(ActionEvente){Stringnumber=e.getActionCommand();intn=Integer.parseInt(number);intm=n*n*n;a.text3.setText(n+"的立方是:"+m);}}2．importjava.applet.*importjava.awt.*;importjava.awt.event.*;publicclassZuoYe13_2extendsAppletimplementsMouseListener{finalintnumber=38;intcount=0;Image[]card=newImage[number]; publicvoidinit(){addMouseListener(this);for(inti=0;inumber)count=0;repaint();}publicvoidmouseReleased(MouseEvente){}publicvoidmouseEntered(MouseEvente){}publicvoidmouseExited(MouseEvente){}publicvoidmouseClicked(MouseEvente){}}'