武科大-java实验答案-全.doc

补充第一节的内容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(程序结束。);1. 上面的程序有几处错误？请依次改正。2. 这个程序的源代码应该保存为什么名字的文件？ 3. 请写出编译和运行这个文件的完整命令，注意给出环境变量的设置（假设源文件保存在d:java目录）4. 如果在程序最前面加入下面语句：package Pkg;该程序又该如何编译和运行？答案：答案（1）：修改以后的程序为（粗体为修改过的地方）public class MyJavaClass int a; MyJavaClass(int a)this.a=a; public Static void main(String args) MyJavaClass c1=new MyJavaClass(2) /此处的实际参数可为任意整数; System.out.println(c1.a); System.out.println(程序结束。); 答案（2） public class MyJavaClass int a; int myjavaClass(int a)this.a=a;return a;/注此处函数返回值可为任意类型public static void main(String args) MyJavaClass c1=new MyJavaClass(); System.out.println(c1.a)；System.out.println(程序结束。); 2、答案：这个程序的源代码应该保存为MyJavaClass.java。 3、答案(1)set class=c:j2sdkbin set classpath=d:java 编译：javac d:javaMyJavaClass.java 运行：java MyJavaClass 答案（2）编译：c:j2sdkbinjavac d:javaMyJavaClass.java set classpath=d:java 运行：java MyJavaClass 4、答案：如果在程序最前面加入语句：package pkg;环境变量同3、设置编译：javac -d . d:javaMyJavaClass.java 运行：java pkg.MyJavaClass I 实验1答案1-(1-1)：import java.io.*;class RandomMonthpublic static void main(String args) String months=January,February,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, Aguest,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+) 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 in=new BufferedReader(new InputStreamReader(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=new Student(info0,info1,Float.parseFloat(info2),Float.parseFloat(info3); for(i=0;is.length;i+) if(isEnroll(si) System.out.println(+ +si.id + + 被录取!); else System.out.println(+ +si.id + + 没有录取!); 2-(3)思考题：import java.io.*;class Complex double RealPart; double ImageinPart; Complex(double rp,double ip) RealPart=rp; ImageinPart=ip; Complex complexAdd(Complex 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)+i); else return (RealPart+ImageinPart*+i); class ComplexApp public static void main(String args)char operator; try Complex 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=plexMinus(c2);break; System.out.println(complexResult); catch(IOException e) System.out.println(e); III实验3 答案3-(1)1、class Person public 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;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+ ); return name=+name+ sex=+sex + age=+age+ sno=+sno+ classno+classno+ ; ;public class TestStudentpublic static void main(String args)Student s1=new Student(susan,女,20,20031015123,2); s1.updateAge(21); s1.toString();3-(3)import java.util.*;abstract class Employee String name; long no; static long id=1000; abstract double getPay(); Employee(String name) =name;id=id+1; ;class Manager extends Employee double 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(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; public String toString()return name:+name+ no:+no+ pay:+getPay();class EmployApp public 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.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(总工资:+numPay);IV 实验4 答案4-(1)import java.lang.*;import java.io.*;class TestException public static void main(String args) tryoutofBound();arraySize();nullPointer();catch(NegativeArraySizeException e)System.out.println(e.toString();static void outofBound() try int i;int a; a=new int10; for(i=0;i11;i+) ai=i; System.out.println(a+i+=+ ai); catch(IndexOutOfBoundsException e)System.out.println(e.toString(); static void nullPointer() try String s=null; System.out.println(s.length(); catch(NullPointerException e)System.out.println(e.toString(); static void arraySize() throws NegativeArraySizeException try int a; a=new int-3; catch(NegativeArraySizeException e)throw e;4-(2)class MyException extends Exceptionprivate String Msg;public MyException(String message)super(message);Msg=message;public void printMsg()System.out.println(Msg);public class EX6_3void GenerateMyException() throws MyExceptionthrow new MyException(此处发生异常信息);public static void main(String args)EX6_3 obj=new EX6_3();tryobj.GenerateMyException();catch (MyException e)e.printMsg();4-(3)思考题class NullParameterException extends Exception NullParameterException(String Message)super(Message); ;class TestArea public static void main(String args) shape sh=null;int num;num=args.length;tryswitch(num)case 1:sh=new Zangle(Double.parseDouble(args0); break;Case 2:sh=new Longangle(Double.parseDouble(args0),Double.parseDouble(args1);break;case 3:sh=new Triangle(Double.parseDouble(args0),Double.parseDouble(args1),Double.parseDouble(args2);break;case 0:throw new NullParameterException(参数个数为零！);System.out.println(sh.area();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 shapedouble 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 实验5 答案5-(1)import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.FileWriter;import java.io.IOException;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=+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(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() try PrintWriter 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(); try Scanner 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 TestStudentAll public static 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(学号雷同); stSet.addStudent(new Student(ccc,003,21); stSet.displayAllStudent(0); stSet.saveStudent(); */ stSet.displayAllStudent(1); stSet.removeStudent(002); System.out.println(n删除后信息); 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()System.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() 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() try PrintWriter 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(); try Scanner 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 TestStudentAll public static 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(学号雷同); stSet.addStudent(new Student(ccc,003,21); stSet.displayAllStudent(0); stSet.saveStudent(); */ stSet.displayAllStudent(1); stSet.removeStudent(002); System.out.println(n删除后信息); Collections.sort(stSet.studentSet,new NameComparator(); stSet.displayAllStudent(0); class NameComparator implements Comparator public int compare(Object obj1,Object obj2) Student e1=(Student)obj1; Student 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