Final Examination Semester 3 / Year 2012

Transcription

1 Final Examination Semester 3 / Year 2012 COURSE : OBJECT-ORIENTED PROGRAMMING COURSE CODE : PROG 2013 TIME : 2 1/2 HOURS DEPARTMENT : COMPUTER SCIENCE LECTURER : LIM PEI GEOK Student s ID : Batch No. : Notes to candidates: 1) The question paper consists of 7 pages Section A: 10 questions (20 marks) Section B: 2 questions (20 marks) Section C: 2 questions (60 marks) 2) Answer all questions. 3) Write your answer for Section A and Section B in answer booklet. 4) Save your answer for questions in Section C and submit your answers in softcopy to Southern College E-Learning System.

2 SECTION A: MULTIPLE CHOICE QUESTION (10 X 2 = 20 MARKS) Please choose most appropriate answer. State the answer in the answer booklet. 1. Which of the following groups of overload constructors are valid? a. public Cat(int age) { public Cat(double wgt) { b. public Dog(String name, double weight) { public Dog(String name, double height) { c. public Dog(String name, double weight) { public Dog(double weight, String name) { d. public Cat(String name) { public Cat(String weight) { 2. Assume a working program contains the following statement: mydog.setname( Bowser ); Which of the following do you know? a. setname() is a public method b. setname() accepts a string parameter c. Both of these d. None of these 3. A subclass inherits from its superclasses. a. private data b. protected data c. public data d. b and c 4. The method tostring() is a public member of the class. a. Object b. Writer c. String d. Output 5. You can use to check whether an object is an instance of a class. a. new b. static c. instanceof d. super 6. Suppose that Car and Motorcycle are subclass of Vehicle. Which of the following statement is VALID for create an object of Car? a. Vehicle a = new Car(); b. Car a = new Motocycle(); c. Vehicle a = new Motocycle(); d. Car a = new Vehicle(); 1/6

3 7. If more than one method shares the same name, then we say they are overloaded methods. Which of the following condition will make the overloaded methods invalid? a. The number of parameters is different. b. The number of parameters is same, but the data types of the parameters are different. c. Both of the number of parameters and data types of the parameters is the same. d. Both of the number of parameters and the data types of the parameters is different. 8. Which of the following statements is TRUE? a. A subclass inherits all the member of its superclass. b. A subclass inherits the public members of its superclass. c. A subclass inherits only the private members of its superclass. d. A subclass inherits none of the members of its superclass. 9. An interface can extends interface/s. a. none b. only one c. one or more d. All of above 10. Which of the following class definitions defines a legal interface class? a. interface A{ b. void print(){ ; c. abstract interface A{ d. print(); abstract interface A extends T1,T2{ Abstract void print() {; interface A{ void print(); 2/6

4 SECTION B: SHORT QUESTIONS (20 MARKS) Answer all the questions in answer booklet. Question 1 (10 marks) a. What is the output for the following codes? (6 marks) public class TestInstanceOf { public static void main (String ary[ ]){ display(new Box()); display(new WoddenBox()); display(new String("hello")); public static void display(object x) { System.out.println(x.toString()); class Box{ public String tostring(){ return "This is a simple box"; class WoddenBox extends Box{ public String tostring( ){ return "This is a Wodden box"; b. There is one error in the following codes. Identify the error and rewrite the statement with correct codes. (4 marks) 1 class Vehicle { 2 abstract public void getvin(); 3 Question 2 (10 marks) a. What modifier should you use on a class so that a class in the different package cannot access it, but its subclasses in any package can access it? (2 marks) b. If a method in a subclass has the same signature as a method in its superclass with the same return type, is the method overridden or overloaded? (2 marks) c. If a class implements Comparable, the object of the class can invoke the compareto method. Indicate true or false. (2 marks) 3/6

5 d. Can you invoke the clone() method to clone an object if the class for the object does not implement the java.lang.cloneable? (2 marks) e. Give an example of the classes in the Java library that implement Cloneable. (2 marks) 4/6

6 SECTION C: CODING QUESTIONS (60 MARKS) Submit your answer in softcopy and upload it to Southern E-Learning System. Question 1 (40 marks) The IT manager of the CassaFashion Company hired you to work on their online-ordering system. All the items sold in RM 30 in the online system. Your job scope is to calculate the total payment of their order. Basically, there are two types of delivery method which include shipping and self-collection. Complete the following task: a) Create a class named Order that include data fields that hold customer name (Example: Mary Chia ) and quantity order. Write two constructors which include a default constructor and a constructor that requires the customer name and quantity order. Write the accessor and mutator method for all the attributes in Order class. Write a method with double return type named as computeprice() to compute the total price of the order. Override the tostring() method to display the attributes of the class Order. (19 marks) Attributes/Methods double computeprice() double tostring() Descriptions Calculate and return the total payment by using the following formula: Total price = quantity x unit price It will return the customer name, quantity order, unit price and total price. Example: Order Details***** Customer name : Mary Chia Quantity Order : 10 Unit Price : RM 30 Total Price : RM b) Create a subclass named ShippedOrder. The class has two data fields which include weight of parcel and shipping address. Write an appropriate constructor for this class. Write the accessor and mutator methods for all the attributes in ShippedOrder class. Override the computeprice() method to add in the delivery charges. Override the tostring() method to display the shipping address and total price. (21 marks) The delivery charges will be calculated as follows: Parcel weight (kg) Cost per kg (RM) <3 kg RM 4.50 per kg 3 8 kg RM 3.85 per kg >8 kg RM 2.00 per kg 5/6

7 Attributes/Methods Descriptions double computeprice() Calculate the total payment by adding the delivery charge based on the table above. double tostring() It will return the customer name, quantity order, unit price, total price, weight, overall payment and shipping address. Example: Order Details***** Customer name : Mary Chia Quantity Order : 10 Unit Price : RM 30 Total Price : RM Weight (KG): 2 Total Price (Include shipping fee): RM The item/s will be deliver to No. 17, Jalan Fatimah 2, Taman Johor Question 2 (20 marks) Write a class named FixedInvestment that implements the Comparable interfaces. Required: a) A double data field named depositamout that specifies the investment amount (default 1000). b) A double data field named annualinterestrate that specifies the fixed interest rate. (default 5.0%) c) An int data field named numberofyear that specifies the investment duration. (default 1) d) A constructor that create an instance with the specified depositamount, annualinterestrate and numberofyear. e) Accessor and mutator methods for all the data fields. f) A gettotalreturn() method that returns the investment return after the specified number of years. The total return can be computed using the following formula: numberofyear x 12 totalreturn = investmentamount x (1+monthlyInterestRate) The objects of FixedInvestment class should compare based on their total return /6