CSIS 10A PRACTICE FINAL EXAM Name Closed Book Closed Computer 3 Sheets of Notes Allowed

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1 CSIS 10A PRACTICE FINAL EXAM Name Closed Book Closed Computer 3 Sheets of Notes Allowed MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) What would be the results of the following code? int[] array1 = new int[25]; // Code that will put values in array1 int value = array1[0]; for (int a = 1; a < array1.length; a++) { if (array1[a] < value) value = array1[a]; A) value contains the lowest value in array1 B) value contains the average of the values in array1 C) value contains the highest value in array1 D) value contains the sum of all the values in array1 1) 2) A partially-filled array is normally used 2) A) When you know how many elements will be in the array B) To display array elements C) With an accompanying integer value that holds the number of items stored in the array D) With an accompanying parallel array 3) To return an array of long values from a method, use this as the return type for the method. 3) A) long[ ] B) long C) [ ]long D) long[arraysize] 4) Which of the following is not true about static methods? 4) A) They are often used to create utility classes that perform operations on data, but have no need to collect and store data. B) It is not necessary for an instance of the class to be created to execute the method. C) They are created by placing the key word static after the access specifier in the method header. D) They are called from an instance of the class. 5) If you have defined a class named SavingsAccount with a public static data member named numberofaccounts, and created a SavingsAccount object referenced by the variable account20, which of the following will assign numberofaccounts to numaccounts? A) numaccounts = numberofaccounts; B) numaccounts = SavingsAccount.numberOfAccounts; C) numaccounts = account20.numberofaccounts; D) None of the above, you cannot reference a static data member. 5)

2 6) To compare two objects in a class, 6) A) Use the ==, e.g. object1 == object2 B) Since objects consist of several fields, you cannot compare them C) Write a method to do a byte-by-byte compare of the two objects D) Write an equals method that will make a field by field compare of the two objects 7) The Character wrapper class provides numerous methods for 7) A) Testing String objects B) Converting String variables C) Testing and converting char variables D) Adding two char variables 8) What will be printed after the following code is executed? String str = "abc456"; int m = 0; while ( m < 6 ) { if (Character.isLetter(str.charAt(m))) System.out.print( Character.toUpperCase(str.charAt(m))); m++; 8) A) abc456 B) ABC456 C) 456 D) ABC 9) When you are writing a program with String objects that may have unwanted spaces at the beginning or end of the strings, use this method to delete them. A) valueof B) substring C) replace D) trim 9) 10) When an "is a" relationship exists between objects, it means that the specialized object has 10) A) Some of the characteristics of the general class, but not all, plus additional characteristics B) Some of the characteristics of the general object, but not all C) None of the characteristics of the general object D) All the characteristics of the general object, plus additional characteristics 11) If ClassA is derived from ClassB, then 11) A) Neither public or private members in ClassB can be directly accessed in ClassA B) Public members in ClassB are public in ClassA, but private members in ClassB cannot be directly accessed in ClassA C) Public and private members of ClassB are public and private, respectively, in ClassA D) Private members in ClassB are changed to protected members in ClassA 12) Applets are important because they can be used to. 12) A) Run other programs on the user's system B) Process large data files C) Extend the capabilities of a Web page D) Keep the doctor away

3 1) (5 points) What would be the output when the following code block executes? int a=3, b=8, c=2; if (a < b && b < c) b = b + 2; if ( b > 5 a < 3) a = a 1; if ( c!= 8 && b > 5) c = 8; System.out.println(a + " " + b + " " + c); OUTPUT: 2) (5 points) Complete the next 4 lines of the trace table for the following code: int sum = 0, m = 10; for (int k=0; k<10; k=k+2){ sum = sum + m; m = m - 2; sum m k k< T 3) (10 points points) What will be displayed on the terminal by the following nested loop? for (int k = 1; k < 3; k ++ ){ for (int m = 0; m < k ; m ++){ System.out.print( m ); System.out.println();

4 4) (20 points) Here is a class for representing Employees at a work place. Complete the constructor and the three methods indicated according to the javadoc comments provided. You don't have to write the javadocs Constructor Summary Employee(String name, double wage) creates a new Employee object with a given name, and hourly wage. Method Summary String getname() returns the name of the employee void setwage(int newwage) changes the wage to newwage double calcpaycheck(double hours) returns the pay check for an employee based on the hourly wage times the number of hours public class Employee { // instance variables private String name; // employee name private double hourlywage; // employee wage // constructor // getname // setwage // calcpaycheck

5 4) (5 points) Complete the folowing main test app to print out the pay check for Employee e (just 2 lines of code) public class EmployeeApp { public static void main(string [] args){ Employee e = Employee("Ben", 25); double pay; // a)calculate pay given that Ben worked 10 hours and store in pay // b)print the pay for Ben 6) (10 points) Draw a map of memory after the following statements execute: Employee a = new Employee("Gil", 25); Employee b = new Employee("Jan",30); Employee c = b; c.setwage(40);

6 7) (10 points) Suppose that a company has 500 employees and that information about all the employees has already been stored in an array Employee [] workers = new Employee[500]; Write a code segment that will: a) Print the names of all the employees in the company b) Compute and print the sum of all pay checks for the entire company, assuming everyone worked 40 hours. Print just one number, the sum of all the paychecks. 8) (10 points) Suppose we have an array of int declared with the following values: int [] data = {7, 5, 1, 2, 4, 5, 3, 6; and, we execute the statements: for (int k = 0; k<7 ; k++) { data[k] = data[k+1]; Please draw the data array after the statements have completed:

7 9) (10 points) We've created a 2D array of integers int[][] table = new int[3][4]; Fill in the values contained in the table after the following statements execute: table for (int row=0; row<3; row++){ for (int col=0; col<4; col++){ if (col == 2) table[row][col] = 7; else table[row][col] = 0;

8 10) (15 points) Complete the following short applet. When it starts up, the applet should display the message "Falling" at location 100,100. Whenever the user clicks (does a mousepress) on the applet, the message should move down the screen 10 pixels. Use the paint() method to display the message. You will need to add an instance variable to keep track of the vertical location of the message. class Falling extends Applet { public void init() { addmouselistener(new MyMouseListener()); public void paint(graphics g) { ; private class MyMouseListener implements MouseListener { public void mousepressed(mouseevent e) { public void mousereleased(mouseevent e) { // Methods required by public void mouseclicked(mouseevent e) { // the MouseListener public void mouseentered(mouseevent e) { // interface. public void mouseexited(mouseevent e) { // end class MyMouseListener // end class Falling