软件学院_面向对象程序设计_2008-2009(2)期末B卷

1、.华南农业大学期末考试试卷（ B卷）2008-2009学年第 2 学期考试科目：面向对象程序设计考试类型：（闭卷）考试时间：120分钟学号姓名年级专业_题号一二三四五总分得分评阅人一、选择题（ 30分）说明：每题2 分，只有1 个正确答案，请将正确答案填写在下面表格中。题号123456789101112131415答案1 Which of the following statements is correct about Java packages?A. A package may contain unlimited number of nested sub-packages.B. A pac

2、kage is a collection of related Java source program.C. Using the import statement can include all the classes into the current program from a specified package and its sub-packages.D. If there is no package statement used, the current class will not be in any package. 2 Which one is the wrong statem

3、ent about Java constructors?A.The name of a constructor must be the same as its classs name.B.A constructor has no return value and can not be modified byvoid .C. A constructor of the parent class can not be inherited by its sub-classes.D. All constructors must be modified bypublic.3 Giving the code

4、 bellow:class Testprivate int m;public static void fun() /* some code. */ How to make the member variable maccessible for method fun()?A.change private int m to protected int mB.change private int m to public int m.C. change private int m to static int mD. change private int m to int m 4 Whichofthef

5、ollowingfunctionsisanoverloadingfunctionof publicvoidexample().?A. public void example().B. public int example().C. public void example2().D. public int example(int m, float f).5 In Java, a class may have many different methods with the same name. The number, type,sequences of arguments in these met

6、hods are different, and the return value can be different as well. What do we call this feature in terms of object-oriented programming?A.HidingB.OverridingC. OverloadingD. This feature is not supported in Java6 How to execute the following program?public class Testpublic static void main(String arg

7、s) System.out.println(args0);A.java Test.classB.java TestC. java Test aStringD. javac Test7 If a container has been resized, which of the following layout manager did not change the internal components size?A.CardLayoutB.FlowLayoutC. BorderLayoutD. GridLayout8 Which is the right statement about exce

8、ption handling?A. In java, all exceptions are necessary to be caught and handled.B. The “catch ”statement catches exception by type-matching.C. In the “try-catch-finally ”structure, the program will exit after exception handling.D. Exception is a kind of errors, and it should be absolutely avoided i

9、n programs.9 The following statements are about type-casting, which one is correct?A. A reference variable of a class can only be assigned to an object of its first level sub-classes of this class.B. An object can not be casted to the type of another class which has no inheritance.relationship with

10、the object s original class.C. A child class s reference variable can be assigned to an object of its parent class.D. There is only explicit casting, but no implicit casting.10 Both class Teacher and Student are the sub-classes of Person . Person p; Teacher t; Student s; / assume p, t and s are not

11、null if(t instanceof Person) s = (Student)t; Which statement about the last line of expression is correct?A. A new Student object will be created.B. The type-casting is correct.C. The expression is incorrect.D. There is no syntax error but will generate runtime error.11 According to the code below,

12、which statement is correct?public class Test static Object o;public static void main(String args) System.out.println(o);A. Generates compile error.B. Compiles OK, but has runtime errors.C. Outputs zero.D. Outputs “null ”.12 According to the code below, select the statement which is false.String s =

13、Hello;String s1 = new String(Hello);String s2 = ern();String s3 = Hello;A.s1 = sB.s2= sC.s = s3D.s2= s313 The array definition code is given below, which statement is correct?String s = new String10;A.The definition of arrays is illegal in syntax.B. s is a 10 10two-dimensional array.C. All ele

14、ments in s are .D. s is an array of ten arrays.14 Which is the correct output according to the program given bellow?public static void main(String args)Scanner scanner = new Scanner(this is one that is two); scanner.useDelimiter( is); / there is a space before is.while(scanner.hasNext() System.out.p

15、rint(scanner.next();A.this one that twoB.th one that twoC. thone that twoD. this is one that is two15 The file “empty.txt”does not exist before, what its content will be after executing thefollowing code.public static void main(String args) throws FileNotFoundException PrintWriter pr = new PrintWrit

16、er(new File(empty.txt);pr.print(onettwo);pr.append(n1t2);pr.close();A.one twoB.onettwo121t2C. onettwon1t2D. one two 1 2二、改错题（20 分）说明：写出每段代码的错误原因并改正错误，每小题4 分，说明原因和改正各2 分。1 class First import java.io.*;package mypackage;class Second 2 class A String name;public A(String s) name = s; class B extends A

17、int id;public B (int i) id = i; 3 class Alpha private void m() .public void p() class Beta extends Alpha public void m() private void p() 4 interface Base void m();void n();class Child implements Base public void m() System.out.println(this is method m);5 public class B extends A final void increase

18、() value += 2;class A int value = 0;final void increase() value += 1;三、程序阅读题（20 分）说明：阅读下面程序并写出它们的输出结果，每小题5 分。1 The program is as below:.class Aint h = 1;public A(int h)h = h;System.out.println(this.h);this.h = h;System.out.println(this.h);public static void main(String args)A a = new A(2);2 The prog

19、ram is as below:class Base public Base() System.out.println(What a pleasure!);public Base(String s) this();System.out.println(I am + s + !);public class Child extends Basepublic static void main(String args) Child t = new Child(Mike);public Child(String s) super(s);System.out.println(How do you do?)

20、;public Child() this(I am Tom);.3 The program is as below:class DivTest public static void main(String args) int r, n, d;n = 10; d = 0;try r = n / d;System.out.println(r= + r); catch(ArithmeticException e) System.out.println(Divide 0 exception!); finally System.out.println(Calculation complete!);Sys

21、tem.out.println(Program finish!);4 Analyze the program bellow, and explain its effect.public class MyFrame extends JFrame JButton b1, b2;public MyFrame() ActionListener a = new ActionListener() public void actionPerformed(ActionEvent evt) if (evt.getSource() = b1) b1.setEnabled(false);b2.setEnabled(

22、true); else b1.setEnabled(true);b2.setEnabled(false);setLayout(new FlowLayout();b1 = new JButton(1); b1.addActionListener(a); add(b1);b2 = new JButton(2); b2.addActionListener(a); add(b2); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);.setSize(150, 100);setVisible(true);public static void main(Stri

23、ng args) new MyFrame();四、应用设计题（6 分）The following classes are a part of the classes founded in a companys personnel management system, find out their relationships and illustrate using a UML class diagram.Employee, long-tern employee, temporal employee, manager, temporal salesman.五、程序设计题（24 分）说明：按照题目

24、要求编写下面两段程序。1Write a java application program containing these classes:Person , Student , TestStudent.The details are: Class Person Properties name: String sex: charid : Stringphone: Stringemail : String MethodsPerson(Name name, char sex, String id): constructorString getId()void setEmail(String emai

25、l)void setPhone(String phone)String toString(): outputs a persons informationClass StudentA sub-class derived from Person, more properties are added:PropertiessNo: longsClass : StringMethodsStudent(long sNo, String name, char sex, String id): constructorsetClass(String sClass)String toString(): outp

26、uts a students information Class TestStudentA class used as the main class to test the functions.use the following information to create a student object,aStudent .Name:Guo YangSex:maleID:22033198807070333sNo.:2004002 set other information to aStudent . E-mail: Phone:88078549output all the information ofaStudent .2 Calculate the sum ar