INTRODUCTION TO SOFTWARE SYSTEMS (COMP1110/COMP1140/COMP1510/COMP6710)

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1 Important notice: This document is a sample exam. The final exam will differ from this exam in numerous ways. The purpose of this sample exam is to provide students with access to an exam written in a similar style and with a similar structure to their final exam. Both this sample exam and the final exam sample material from the entire semester, but the selection will be different in the final exam to what is presented here. INTRODUCTION TO SOFTWARE SYSTEMS (COMP1110/COMP1140/COMP1510/COMP6710) Writing period: 3 Hours duration Study period: 15 Minutes duration Permitted materials: None You must attempt to answer all questions. Questions are not of equal value. All questions must be completed on this exam paper. This examination paper must not be taken out of the exam room. Student ID: Course Code: Please do not write in the grey boxes that appear throughout the exam paper. These are for use by markers. Q1 Q2 Q3 Q4 Q5 Q6 /10 /10 /35 /20 /15 /10 /100 Page 1 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

2 Question 1. [10 Marks] Imperative Programming Given the following code: import java.util.arraylist; import java.util.list; public class Simple { private static String foo(int i) { String result = ""; if (i < 2) return result + i; else { for (int j = i; j >0; j--) { result += j; return result + foo(i-1) + foo(i-2); public static void main(string[] args) { List<Integer> list = new ArrayList<Integer>(); list.add(1); list.add(2); list.set(0, 0); System.out.println("A: "+list); list.remove(1); System.out.println("B: "+list); System.out.println("C: "+list.get(0)); System.out.println("D: "+foo(3)); Note: The tostring() method of ArrayList will print in the format [ 1, 2, 3 ] (for a list of 1, 2, and 3). Write in the box below exactly what the program will output when it is run. Q1 /10 Page 2 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

3 Question 2. [10 Marks] Multiple choice Read the following carefully: Given the following 15 True/False questions, mark either True or False (but not both). Each question that is correctly answered gains you 1 mark, each question answered incorrectly loses you 1 mark, a question left unanswered neither loses nor gains marks. The final mark for this question is calculated by bounding the sum of marks between 0 and 10. For example, if you answered all questions correctly you would gain 10 (not 15) for this question. If you answer 8 correctly, 2 incorrectly and leave the remaining 5 unanswered you would gain 6/10 for this question. If you wish to change your answer then cross off both True and False and clearly state your answer in words. (e.g. I would like to leave this question unanswered. or My answer is True. ) Basic Java a) true false is equal to true. True False b) ((int) 2.4) / 2 is equal to 1.2. True False c) An if statement must always be followed by an else statement. True False Object Oriented Programming d) A Java class can inherit from multiple classes. True False e) An object is an instantiation of a class. True False f) An Interface cannot include method implementations. True False g) Anonymous inner classes are useful for passing code to methods. True False Abstract Data Types h) A binary search tree can be used to implement a set. True False i) A linked list is an efficient way to implement a map. True False j) An array can be used to implement a list. True False Complexity k) Finding an element in a well-designed hash table is O(1). True False l) Finding an element in a linked list is O(Log N). True False Software Engineering m) Test driven development begins with a test that fails. True False n) A mercurial changeset that has two children indicates a branch. True False o) Formal verification is important for safety critical software. True False Q2 /10 Page 3 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

4 Question 3 [35 Marks] Software development This question concerns a small piece of software for keeping track of stock in a grocery store. The software will reduce stock each time stock is sold, increase stock each time new stock arrives, and correct stock levels every time a careful count is made of the actual stock on the store s shelves (this activity is called a stock take ). Each item for sale is called a product. Every product has: a string that uniquely identifies it called a stock-keeping unit or SKU (e.g. 473C2D ); a target stock level, a current stock level; and a name, a human-readable string that describes it (e.g. Vegemite, 500g, or Apple, Granny Smith ). There are two categories of item: unit items and bulk produce. Unit items are sold by count (e.g. 2 jars of jam), and stock is counted in units. Bulk items are sold by weight (e.g. 450g of apples), and stock is counted in kilograms (and may be fractions). Your client is a grocer who has asked you to write software that has the following public interface: public interface StockManager { * A new product has been introduced sku The product s sku name The product s name price The product s price (per unit for units or per kg for bulk) bulk True if the item is a bulk item, false if it is a unit item public void newitem(string sku, String name, double price, boolean bulk); * An product has been sold; reduce current stock accordingly. sku The product s sku sold The quantity sold public void sale(string sku, double sold); * New stock has arrived; increase current stock accordingly. sku The product s sku added The quantity newly arrived public void addstock(string sku, double added); * Set the target amount of stock for a product. sku The item s sku target The target quantity desired to be held in stock public void targetstock(string sku, double target); * Stock has been carefully counted. Set current stock correctly. sku The product s sku actual The quantity actually in the store The stock loss or gain (new current old current) public double stocktake(string sku, double actual); * Print one line for each item in the store with the SKU, the name, * and the amount needed to reach the target stock level. public void printorderreport(); Page 4 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

5 3 i) [10 Marks] In the space below, draw a UML class diagram for your class MyStockManager (which implements the StockManager interface), and any other classes that your class will depend on, excepting those classes that are part of the standard Java library (e.g. String, etc). /10 Page 5 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

6 3 ii) [5 Marks] In the space below, write a declaration of MyStockManager, including all of its fields, but excluding all methods. This should be consistent with the UML diagram for the class in 3i). /5 3 iii) [5 Marks] In the space below, write an implementation of the newitem() method. public void newitem(string sku, String name, double price, boolean bulk) { /5 3 iv) [5 Marks] In the space below, write an implementation of the sale() method. public void sale(string sku, double sold) { /5 Page 6 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

7 3 v) [5 Marks] In the space below, write a unit test for the sale() method from 3 public void saletest() { /5 3 vi) [5 Marks] In the space below, write an implementation of the printorderreport() method. public void printorderreport() { /5 Q3 /35 Page 7 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

8 Question 4. [20 Marks] Abstract data types Consider the following skeleton implementation of a simple list ADT based on an array. public class ArrayList<V> { static final int INITIAL_SIZE = 4; static final double GROWTH_FACTOR = 1.5; int elements = 0; // the number of elements in our list V[] values = (V[]) new Object[INITIAL_SIZE]; * Add a value to the tail of the list. value The value to be added. public void add(v value) { /* unimplemented * Remove the value at the specified index from the list. index public void remove(int index) { /* unimplemented index The value at the specified index. public V get(int index) { if (index >= elements index < 0) throw new IndexOutOfBoundsException(); return values[index]; * Reverse the order of the elements of the list. public void reverse() { /* unimplemented Page 8 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

9 4 i) [7 Marks] In the space below, provide an implementation of the missing add(v value) method. /7 4 ii) [7 Marks] In the space below, provide an implementation of the missing remove(int index) method. /7 Page 9 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

10 4 iii) [6 Marks] In the space below, provide an implementation of the missing reverse() method. /6 Q4 /20 Page 10 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

11 Question 5 [15 Marks] Threads, Complexity, and Grammars 5 i) [5 Marks] Describe a situation in which a race condition is likely to arise. /5 5 ii) [5 Marks] Discuss the computational complexity of using a linked list to implement a set. Use big-o notation in your answer. /5 5 iii) [2 Marks] Define an EBNF grammar for four-digit binary numbers (e.g. 1010, 1111, 0001, 1000, etc). /2 5 iv) [3 Marks] Define an EBNF grammar for dates, in the format dd/mm/yy (e.g. 02/11/12, 31/10/11 etc). /3 Q5 /15 Page 11 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

12 Question 6 [10 Marks] You must answer only one of 6a) or 6b), choosing according to your degree program. 6 a) (COMP1110, COMP1140, COMP6710 students only) Use the space below to discuss the strengths and weaknesses of Java as a general purpose programming language. Your discussion should contain five major points that you clearly identify. Draw comparisons with other languages where appropriate. 6 b) (COMP1510 students only) In 1996, a $500M Ariane rocket self-destructed on launch. A report concluded that a program segment for converting a floating point number to a signed 16 bit integer was executed with an input data value outside the range representable by a signed 16 bit integer. Use the space below to discuss what lessons this incident offers software engineers. Your discussion should structured around five clearly identified major points. Please circle your degree program: COMP1110 COMP1140 COMP1510 COMP6710 Q6 /10 Page 12 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

13 You may use this box as extra space for completing answers to previous questions. Please indicate clearly which question(s) you are continuing. Q1 Q2 Q3 Q4 Q5 Q6 Page 13 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )

14 You may use this box as extra space for completing answers to previous questions. Please indicate clearly which question(s) you are continuing. Q1 Q2 Q3 Q4 Q5 Q6 Page 14 of 14 - INTRODUCTION TO SOFTWARE SYSTEMS ( COMP1110/COMP1140/COMP1510/COMP6710 )