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1 CIS 265 Sect 01 - V. Matos Exam-2 Spring-2015 First Name Last Name ID# (15 pts) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) In the following method, what is the base case? 1) static int xmethod(int n) { if (n == 1) return 1; else return n + xmethod(n - 1); A) n is 1. B) n is greater than 1. C) no base case. D) n is less than 1. 2) What is the return value for xmethod(4) after calling the following method? 2) static int xmethod(int n) { if (n == 1) return 1; else return n + xmethod(n - 1); A) 12 B) 9 C) 10 D) 11 3) Analyze the following code: 3) public static void main(string[ ] args) { int[ ] x = {1, 2, 3, 4, 5; xmethod(x, 5); public static void xmethod(int[ ] x, int length) { System.out.print(" " + x[length - 1]); xmethod(x, length - 1); A) The program displays B) The program displays C) The program displays and then raises an ArrayIndexOutOfBoundsException. D) The program displays and then raises an ArrayIndexOutOfBoundsException.

2 4) Analyze the following two programs: 4) A: public static void main(string[ ] args) { xmethod(5); public static void xmethod(int length) { if (length > 1) { System.out.print((length - 1) + " "); xmethod(length - 1); B: public static void main(string[ ] args) { xmethod(5); public static void xmethod(int length) { while (length > 1) { System.out.print((length - 1) + " "); xmethod(length - 1); A) The two programs produce the same output B) Program A produces the output and Program B prints infinitely. C) The two programs produce the same output D) The two programs produce the same output E) The two programs produce the same output ) To declare a class named A with a generic type, use 5) A) public class A<E> {... B) public class A(E, F) {... C) public class A(E) {... D) public class A<E, F> {... 6) Suppose List<String> list = new ArrayList<String>. Which of the following operations are correct? A) list.add(new ArrayList()); B) list.add("red"); C) list.add(new Integer(100)); D) list.add(new java.util.date()); 6) 7) To create a list to store integers, use 7) A) ArrayList<Number> list = new ArrayList<Integer>(); B) ArrayList<int> list = new ArrayList<int>(); C) ArrayList<Object> list = new ArrayList<Integer>(); D) ArrayList<Integer> list = new ArrayList<Integer>();

3 8) Which of the data types below does not allow duplicates? 8) A) List B) Vector C) Stack D) Set E) LinkedList 9) Which of the data types below could be used to store elements in their natural order based on the compareto method. A) Set B) LinkedHashSet C) TreeSet D) Collection E) HashSet 9) 10) Suppose set s1 is [1, 2, 5] and set s2 is [2, 3, 6]. After s1.addall(s2), s1 is. 10) A) [1, 2, 3, 5, 6] B) [1, 2, 2, 3, 5, 6] C) [2] D) [1, 5] 11) The printout of the following code is. 11) LinkedHashSet<String> set1 = new LinkedHashSet<String>(); set1.add("new York"); LinkedHashSet<String> set2 = set1; set1.add("atlanta"); set2.add("dallas"); System.out.println(set2); A) [New York, Dallas] B) [New York, Atlanta] C) [New York] D) [New York, Atlanta, Dallas] 12) If you want to store non-duplicated objects in the order in which they are inserted, you should use. A) ArrayList B) LinkedList C) HashSet D) TreeSet E) LinkedHashSet 12) 13) Which of the following is correct to perform the set union of two sets s1 and s2? 13) A) s1.addall(s2) B) s1.add(s2) C) s1 + s2 D) s1.union(s2) 14) Analyze the following code. 14) import java.util.*; public static void main(string[ ] args) throws Exception { Set set = new TreeSet(); set.add("red"); set.add("green"); set.add("blue"); System.out.println(set.first());

4 A) The program displays Red B) The program may display Red, Blue, or Green. C) The program displays Blue D) The program displays Green E) The program cannot compile, because the first() method is not defined in Set. 15) Which method do you use to test if an element is in a set or list named x? 15) A) (element instanceof List) (element instanceof Set) B) x.in(element) C) x.contains(element) D) x.include(element) E) x.contain(element) 16) Which data type should you use if you want to store duplicate elements and be able to insert or delete elements anywhere efficiently? A) LinkedList B) Vector C) Set D) Stack E) ArrayList 16) 17) Which of the following is correct to create a list from an array? 17) A) new List({"red", "green", "blue") B) new LinkedList(new String[ ]{"red", "green", "blue") C) new ArrayList(new String[ ]{"red", "green", "blue") D) new List(new String[ ]{"red", "green", "blue") E) Arrays.asList(new String[ ]{"red", "green", "blue") (15 pts) Java Programming [Select one of the following two choices] OPTION1. Write a RECURSIVE method to count the number of times a particular word appears in a piece of text. The method accepts two strings (1) text representing the document to be explored, and (2) keyword which is the word to be found in the text. For example, assume text is the good the bad and the ugly and keyword is the word the, the value returned is 3. The method s header follows: public static int countwordoccurrence( String text, String keyword ) OPTION2. Write a program to check whether an expression has correct pairs of grouping symbols. An expression contains various pairs of grouping symbols, such as: 1. Parentheses: ( and ) 2. Braces: { and 3. Brackets: [ and ] For example, the expression (a{b) is illegal. Write a program to check whether an expression has correct pairs of grouping symbols. The method s header follows: public static boolean isbalancedparenthesis ( String expression )

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7 1) A 2) C 3) D 4) B 5) A 6) B 7) D 8) D 9) C 10) A 11) D 12) E 13) A 14) E 15) C 16) A 17) E KEY