武科大java試驗(yàn)答案全

1、補(bǔ)充第一節(jié)的容public class MyJavaClass int a;myjavaclass(int a)this.a=a;public void main() myjavaclass c1=new MyJavaClass();System.out.printIn(c1.a);System.out.printIn( 程序結(jié)束。 );1. 上面的程序有幾處錯(cuò)誤？請(qǐng)依次改正。2. 這個(gè)程序的源代碼應(yīng)該保存為什么名字的文件？3. 請(qǐng)寫出編譯和運(yùn)行這個(gè)文件的完整命令，注意給出環(huán)境變量的設(shè)置(假設(shè)源 文件保存在 d:java 目錄)4. 如果在程序最前面加入下面語句：package Pkg;該程序

2、又該如何編譯和運(yùn)行？答案：答案( 1)：修改以后的程序?yàn)?粗體為修改過的地方)public class MyJavaClass int a;MyJavaClass (int a)this.a=a;public Static void main( String args ) MyJavaClass c1=new MyJavaClass( 2) / 此處的實(shí)際參數(shù)可為任意整數(shù) ;System.out. println (c1.a);System.out.println( 程序結(jié)束。 );答案( 2)public class MyJavaClass int a;int myjavaClass(int

3、 a)this.a=a;return a; / 注此處函數(shù)返回值可為任意類型public static void main( String args ) MyJavaClass c1=new MyJavaClass();System.out. println (c1.a) ； System.out.println( 程序結(jié)束。 );2、答案：這個(gè)程序的源代碼應(yīng)該保存為MyJavaClass.java3、答案 (1)set class=c:j2sdkbinset classpath=d:java編譯：javac d:javaMyJavaClass.java運(yùn)行：java MyJavaClass答

4、案（ 2）編譯：c:j2sdkbinjavac d:javaMyJavaClass.javaset classpath=d:java運(yùn)行： java MyJavaClass4、答案：如果在程序最前面加入語句：package pkg;環(huán)境變量同 3、設(shè)置編譯： javac -d . d:javaMyJavaClass.java運(yùn)行： java pkg.MyJavaClassI 實(shí)驗(yàn) 1 答案1- (1-1) ：import java.io.*;class RandomMonthpublic static void main(String args) String months=January,F

5、ebruary,March,April,May,June,July,Aguest,September,October, November,December;int i;i = (int)(Math.random() * 12);System.out.println(monthsi);1- (1-2)import java.io.*;import java.util.*;class RandomMonth2 public static void main(String args) String months=January,February,March,April,May,June,July,A

6、guest,September,October,November,December;Random r=new Random();int i;i = Math.abs(r.nextInt()%12;System.out.println(monthsi);1-(2)import java.util.*;class RandomPx public static void main(String args) int num=new int20;int i,j,temp;Random r=new Random();for(i=0;i20;i+)numi=r.nextInt();for(i=0;i19;i

7、+)for(j=0;jnumj+1) temp=numj; numj=numj+1; numj+1=temp;for(i=0;i=School.getscoreLine()| (s.getscore()96 & s.getcomScore()=300) ) return true;else return false;public static void main(String args) Student s=new Student3;String info=new String4;int i,j;String messInfo;BufferedReader(newBufferedReader

8、in=newInputStreamReader(System.in);StringTokenizer st;School.setscoreLine(550);for( i=0;is.length;i+ )try messInfo=in.readLine(); st=new StringTokenizer(messInfo); for(j=0;jinfo.length;j+) infoj=st.nextToken(); catch(IOException ex) si=newStudent(info0,info1,Float.parseFloat(info2),Float.parseFloat(

9、i nfo3);被錄取 !);+ 沒 有 錄for(i=0;is.length;i+) if(isEnroll(si)System.out.println(+ +si.id + + elseSystem.out.println(+ +si.id + 取!);2-(3) 思考題：import java.io.*;class Complex double RealPart;double ImageinPart;Complex(double rp,double ip) RealPart=rp; ImageinPart=ip;Complex complexAdd(Compl

10、ex a) Complex temp;temp=new Complex(RealPart+a.RealPart,ImageinPart+a.ImageinPart); return temp;Complex complexMinus(Complex a) Complex temp;temp=new Complex(RealPart-a.RealPart,ImageinPart-a.ImageinPart); return temp;public String toString() if (ImageinPart0)return (RealPart+-+Math.abs(ImageinPart)

11、+i); elsereturn (RealPart+ImageinPart*+i);class ComplexApp public static void main(String args)char operator;tryComplex c1=new Complex(1,2);Complex c2=new Complex(3,4);Complex complexResult;operator=(char)System.in.read();switch(operator) case +:complexResult=plexAdd(c2);break; case -:complexResult=

12、plexMinus(c2);break;System.out.println(complexResult);catch(IOException e)System.out.println(e);III 實(shí)驗(yàn) 3 答案3- (1)1、 class Personpublic String name;public String sex;int age;Person(String name,String sex,int age) =name;this.sex=sex;this.age=age; class Student extends Personpublic String sno;

13、public int classno;public void updateAge(int age)this.age=age;Student(String name,String sex,int age,String sno,int classno) super(name,sex,age);this.sno=sno; this.classno=classno;public String toString() System.out.println(name=+name+ sex=+sex + age=+age+ sno=+sno+ classno+classno+ );sno=+sno+retur

14、n name=+name+ sex=+sex + age=+age+ classno+classno+ ;public class TestStudentpublic static void main(String args) Student s1=new Student(susan, 女 ,20,2); s1.updateAge(21);s1.toString(); 3- (3)import java.util.*;abstract class Employee String name;long no;static long id=1000; abstract double getPay()

15、;Employee(String name) =name;id=id+1;class Manager extends Employeedouble pay=8000;double getPay()return 8000;Manager(String name) super(name);no=id;public String toString()return name:+name+ no:+no+ pay:8000; ;class Sale extends Employee long saleNum;double getPay()return saleNum*0.4;Sale(

16、String name,long saleNum) super(name);no=id;this.saleNum=saleNum;public String toString()return name:+name+ no:+no+ pay:+getPay();class Tech extends Employee long salaryHours;double getPay()return salaryHours*100; Tech(String name,long salaryHours)super(name);no=id;this.salaryHours=salaryHours;publi

17、c String toString()return name:+name+ no:+no+ pay:+getPay(); ;class EmployApppublic static void main(String args) Vector v=new Vector();Employee em;double numPay=0;v.addElement(new Sale(liping,10000);v.addElement(new Sale(susan,12000);v.addElement(new Tech(linda,40);v.addElement(new Tech(write,20);v

18、.addElement(new Manager(gucci);v.addElement(new Manager(jessica);Enumeration e=v.elements(); while(e.hasMoreElements() em=(Employee)e.nextElement(); numPay=numPay+em.getPay(); System.out.println(em);System.out.println( 總工資 :+numPay);IV 實(shí)驗(yàn) 4 答案4- (1)import java.lang.*;import java.io.*;class TestExcep

19、tionpublic static void main(String args)tryoutofBound();arraySize();nullPointer();catch(NegativeArraySizeException e) System.out.println(e.toString();static void outofBound()tryint i;int a;a=new int10; for(i=0;i11;i+) ai=i;System.out.println(a+i+=+ ai); catch(IndexOutOfBoundsException e) System.out.

20、println(e.toString();static void nullPointer()tryString s=null;System.out.println(s.length();catch(NullPointerException e)System.out.println(e.toString();static void arraySize() throws NegativeArraySizeExceptiontryint a;a=new int-3;catch(NegativeArraySizeException e)throw e;4- (2)class MyException e

21、xtends Exception private String Msg;public MyException(String message) super(message); Msg=message; public void printMsg()System.out.println(Msg); public class EX6_3 void GenerateMyException() throws MyException throw new MyException( 此處發(fā)生異常信息 );public static void main(String args) EX6_3 obj=new EX6

22、_3(); tryobj.GenerateMyException(); catch (MyException e) e.printMsg();4-(3) 思考題class NullParameterException extends ExceptionNullParameterException(String Message) super(Message);class TestAreapublic static void main(String args)shape sh=null;int num;num=args.length;tryswitch(num)case 1:sh=new Zang

23、le(Double.parseDouble(args0); break;2:sh=new3:sh=new);Case Longangle(Double.parseDouble(args0),Double.parseDouble(args1);b reak;case Triangle(Double.parseDouble(args0),Double.parseDouble(args1),Dou ble.parseDouble(args2);break;case 0:throw new NullParameterException( 參數(shù)個(gè)數(shù)為零！ System.out.println(sh.ar

24、ea();catch(Exception e)System.out.println(e.toString();abstract class shapeabstract double area();class Triangle extends shapedouble a,b,c;Triangle(double a,double b,double c)this.a=a;this.b=b;this.c=c;double area()double s;s=(a+b+c)/2; return(Math.sqrt(s*(s-a)*(s-b)*(s-c);class Longangle extends sh

25、apedouble l,w;Longangle(double l,double w)this.l=l;this.w=w;double area()return (l*w);class Zangle extends shapedouble l;Zangle(double l)this.l=l;double area()return l*l;V 實(shí)驗(yàn) 5 答案5- (1)import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.FileWriter;import java.io.IOException

26、;import java.io.ObjectOutputStream;import java.io.PrintWriter;import java.io.Serializable;import java.util.*;class Student implements SerializableString name;String sno;int age;Student(String name,String sno,int age) =name;this.sno=sno;this.age=age;void displayInfo()System.out.println(name=

27、+name+sno=+sno+age=+age);String getSno()return sno;int getAge()return age;String getName()return name;class StudentAll Vector studentSet;StudentAll() studentSet=new Vector();boolean addStudent(Student s)boolean flag=true;for(Student se:studentSet)if(se.getSno().equals(s.getSno()flag=false;break;if(f

28、lag) studentSet.addElement(s);return flag;boolean removeStudent(String sno) boolean flag=false;for(Student se:studentSet)if(se.getSno().equals(sno) studentSet.remove(se); flag=true;break;return flag;int getStudentNum() return studentSet.size();void saveStudent()tryPrintWriter ps=new PrintWriter(new

29、FileWriter(sp3.txt); for (Student se:studentSet) ps.print(se.getName(); ps.print( ); ps.print(se.getSno(); ps.print( );ps.println(se.getAge();ps.close();catch(IOException e)void displayAllStudent(int displaySource)String name,sno;int age;if(displaySource=1) studentSet.removeAllElements();tryScanner

30、ps=new Scanner(new FileInputStream(sp3.txt); while(ps.hasNext()name=ps.next();sno=ps.next();age=ps.nextInt();studentSet.addElement(new Student(name,sno,age);ps.close();catch(IOException e)for(Student se:studentSet)se.displayInfo();public class TestStudentAllpublic static void main(String args)int i;

31、StudentAll stSet=new StudentAll();/* stSet.addStudent(new Student(aaa,001,25); stSet.addStudent(new Student(bbb,002,21);if(! stSet.addStudent(new Student(ccc,002,21)System.out.println( 學(xué)號(hào)雷同 ); stSet.addStudent(new Student(ccc,003,21);stSet.displayAllStudent(0);stSet.saveStudent();*/stSet.displayAllS

32、tudent(1);stSet.removeStudent(002);System.out.println(n 刪除后信息 ); stSet.displayAllStudent(0);import java.io.*;import java.util.*;class Student implements SerializableString name;String sno;int age;Student(String name,String sno,int age) =name; this.sno=sno; this.age=age;void displayInfo() Sy

33、stem.out.println(name=+name+sno=+sno+age=+age);String getSno()return sno;int getAge()return age;String getName()return name;class StudentAll Vector studentSet;StudentAll() studentSet=new Vector();boolean addStudent(Student s)boolean flag=true;for(Student se:studentSet) if(se.getSno().equals(s.getSno

34、() flag=false;break;if(flag) studentSet.addElement(s); return flag;boolean removeStudent(String sno) boolean flag=false;for(Student se:studentSet) if(se.getSno().equals(sno) studentSet.remove(se); flag=true;break; return flag;int getStudentNum() return studentSet.size();void saveStudent()tryPrintWri

35、ter ps=new PrintWriter(new FileWriter(sp3.txt); for (Student se:studentSet) ps.print(se.getName(); ps.print( ); ps.print(se.getSno(); ps.print( ); ps.println(se.getAge();ps.close(); catch(IOException e)void displayAllStudent(int displaySource)String name,sno;int age; if(displaySource=1) studentSet.r

36、emoveAllElements();tryScanner ps=new Scanner(new FileInputStream(sp3.txt); while(ps.hasNext() name=ps.next(); sno=ps.next(); age=ps.nextInt();studentSet.addElement(new Student(name,sno,age); ps.close();catch(IOException e)for(Student se:studentSet)se.displayInfo();public class TestStudentAllpublic s

37、tatic void main(String args)int i;StudentAll stSet=new StudentAll();/* stSet.addStudent(new Student(aaa,001,25); stSet.addStudent(new Student(bbb,002,21);if(! stSet.addStudent(new Student(ccc,002,21)System.out.println( 學(xué)號(hào)雷同 ); stSet.addStudent(new Student(ccc,003,21);stSet.displayAllStudent(0);stSet

38、.saveStudent();*/ stSet.displayAllStudent(1); stSet.removeStudent(002); System.out.println(n 刪除后信息 ); Collections.sort(stSet.studentSet,new NameComparator(); stSet.displayAllStudent(0);class NameComparator implements Comparatorpublic int compare(Object obj1,Object obj2)Student e1=(Student)obj1;Stude

39、nt e2=(Student)obj2;if(pareTo()=0) return 0;else if(pareTo()0) return 1;else return -1;import java.io.*;import java.util.*;class Student implements Serializable,ComparableString name;String sno;int age;Student(String name,String sno,int age) =name; this.sno=sno; this.age=age;v

40、oid displayInfo() System.out.println(name=+name+sno=+sno+age=+age);String getSno()return sno;int getAge()return age;String getName()return name; public int compareTo(Object obj) Student p1;p1=(Student)obj;if (p1.ageage)return 1;return 0;class StudentAll Vector studentSet;StudentAll() studentSet=new

41、Vector();boolean addStudent(Student s) boolean flag=true;for(Student se:studentSet) if(se.getSno().equals(s.getSno() flag=false; break;if(flag) studentSet.addElement(s); return flag;boolean removeStudent(String sno) boolean flag=false; for(Student se:studentSet) if(se.getSno().equals(sno) studentSet

42、.remove(se); flag=true;break; return flag;int getStudentNum() return studentSet.size();void saveStudent()tryPrintWriter ps=new PrintWriter(new FileWriter(sp3.txt); for (Student se:studentSet)ps.print(se.getName();ps.print( );ps.print(se.getSno();ps.print( );ps.println(se.getAge();ps.close();catch(IOException e)void displayAllStudent(int displaySource)String name,sno;int age;if(displaySource=1) studentSet.removeAllElements();tryScanner