Exception Handling in Java

1. Answer the following related to exception handling in Java.

(a) An exception is an object that is thrown by a method back to the method that called it to indicate

that a certain type of error occurred that the called method cannot resolve. TRUE / FALSE (1 pt.)

(b) Create an Exception class type named InvalidPasswordException. (1 pt.)

(c) Suppose that there is a void method named ValidatePassword that is passed a username and password, both as a String type, and throws an InvalidPasswordException if the provided password is incorrect for the username passed, otherwise produces no result. Make the changes in the following code to prompt for a specific username and password, and display either Invalid Password Provided, or You are now logged in. (3 pts.)

public static void main(String args[])

{

int num1, num2;

boolean valid_input = false;

Scanner input = new Scanner(System.in);

while (!valid_input)

{

System.out.println(Enter numerator denominator );

num1 = input.nextInt();

num2 = input.nextInt();

try

{

result = quotient(num1, num2);

System.out.println(The result of + num1 + / + num2 + is + result);

valid_input = true;

}

catch ( ArithmeticException ex)

{

System.out.println(Second number entered must be non-zero);

}

}

}

Linked Lists

1. (a) Declare a class named User that contains the following information:

String name

String username

String password

Include in the class a single constructor that is passed a particular name, username, and password; setters and getters, and a toString method that returns the information in a given User object as follows:

"Ashley Smith username: asmith password: aWjPP406!"

(b) Declare a class named UserNode that contains a single User object and a link to another UserNode. Include an appropriate constructor and an appropriate set of methods for this class. (4 pts).

2. Create a class named UserAccounts that maintains a list of users, with an appropriate constructor, and the following methods: (24 pts.)

isEmpty() returns true if list is empty, and false otherwise

findPassword returns the password for a given user name

changePassword updates the password for a given user name and password. If they do not match, the password is not updated.

addUser passed a User object to add

deleteUser deletes a user for a given user name and password. If they do not match, the user is not deleted.

printUsers prints a list of all users, including name, username and password

Stacks and Queues

3. Answer the following questions related to use of stacks.

(a) What is left on the stack after the following stack operations? (3 pts.)

push(10)

push(20)

pop()

push(15)

push(5)

push(40)

pop()

(b) if top = 0 indicates that a stack is empty (for a particular array implementation of a stack) indicate what values are logically on the stack in the following when top = 5. (4 pts.)

0

1

2

3

4

5

6

7

8

9

10

5

28

14

29

32

27

18

34

52

42

23

4. What is left on the queue after the following queue operations? Be sure to indicate where the front of the queue is. (3 pts.)

enqueue(10), enqueue(5), enqueue(20), dequeue(), enqueue(8), dequeue(), enqueue(15)

Recursion

2. (a) Complete the line below for recursive function (method) factorial. (2 pts.)

public static int factorial(int n)

{

if (n == 0)

return 1;

else

return (_____________________);

}

(b) Determine what the following recursive function returns for any value n >= 1. (3 pts.)

public static int func(int n)

{

if(n == 1)

return 2;

else

return 2 * func(n-1);

}

Sorting and Searching / Algorithm Analysis

3. Answer the following questions related to algorithm rate of growth.

(a) If the rate of growth of Algorithm A is O(n²) and Algorithm B is O(n³), it is possible that Algorithm B will be faster than Algoritihm A for certain size input. TRUE / FALSE (2 pts.)

(b) Match the following (draw connecting lines). (4 pts.)

Sequential Search O(nlogn)

Binary Search O(n)

Simple Sorts (Selection Sort, Insertion Sort, BubbleSort) O(logn)

Fastest Sorting Algorithms (QuickSort, MergeSort) O(n²)

4. Give the results of the list below after the first two passes of each of the following sorting algorithms. (4 pts.)

List SELECTION SORT INSERTION SORT BUBBLESORT

10

6

21

14

19

25

8

29

11

4