Ch.7 Questions

What value will be printed in the console after this series of commands? Assume that the ArrayList package has been imported. ArrayList<Integer> array = new ArrayList<Integer>(); array.add(3); array.add(9); array.add(10); array.remove(1); array.set(0, 3); int num = array.get(1); System.out.println(num);

10

Consider the following correct implementation of the insertion sort algorithm: public static int[] insertionSort(int[] arr) { for (int i = 1; i < arr.length; i++) { int curNumber = arr[i]; int curIndex = i-1; while ( curIndex >= 0 && arr[curIndex] > curNumber) { arr[curIndex+1] = arr[curIndex]; curIndex--; //Line 13 } arr[curIndex + 1] = curNumber; } return arr; } The following declaration and method call are made in another method in the same class as insertionSort: int[] nums = {6, 5, 4, 3, 2, 1}; list = insertionSort(nums); How many times is the statement on Line 13 executed as a result of the call to insertionSort?

15

What value will be printed in the console after this series of commands? Assume that the ArrayList package has been imported. ArrayList<Integer> array = new ArrayList<Integer>(); array.add(3); array.add(9); array.add(10); array.remove(1); array.set(0, 3); int num = array.get(1); System.out.println(array.size());

2

How many comparisons will the selection sort algorithm make on an array of 8 elements?

28

Consider the following correct implementation of the selection sort algorithm: 1. public static ArrayList<Integer> selectionSort(ArrayList<Integer> arr) 2. { 3. int currentMinIndex; 4. int counter = 0; 5. for (int i = 0; i < arr.size() - 1; i++) 6. { 7. currentMinIndex = i; 8. for (int j = i + 1; j < arr.size(); j++) 9. { 10. if(arr.get(j) < arr.get(currentMinIndex)) 11. { 12. currentMinIndex = j; 13. } 14. } 15. if (i != currentMinIndex) 16. { 17. int temp = arr.get(currentMinIndex); 18. arr.set(currentMinIndex, arr.get(i)); 19. arr.set(i, temp); //Line 19 20. } 21. } 22. return arr; 23. } Given an ArrayList initialized with the values [6, 5, 4, 3, 2, 1], how many times does Line 19 execute when the ArrayList is sorted using the selection sort algorithm?

3

Consider the following implementation of a search method: public int search(ArrayList<Integer> list, int target) { for(int i = list.size() - 1; i >=0 ; i--) { if(list.get(i) == target) { return i; } } return -1; } An ArrayList nums, is initialized with the values [1, 2, 4, 3, 4, 5]. What value would be returned from the call search(nums, 4)?

4

What will the following code print? ArrayList<Integer> list = new ArrayList<Integer>(); list.add(0); list.add(1); list.add(2); list.add(3); list.add(4); list.add(5); int sum = 0; for (int i = 0; i < list.size(); i+= 2) { sum += list.get(i); } System.out.println(sum);

6

Consider the following code segment: ArrayList<Integer> list = new ArrayList<Integer>(); list.add(5); list.add(10); list.add(15); list.add(20); list.add(25); int counter = 0; while(counter < list.size()) { counter++; list.set(counter, list.get(counter)+5); } System.out.println(list.toString()); What is printed as a result of this code segment?

An IndexOutofBoundsException occurs.

What would the proper initialization and declaration be for an ArrayList myTemps meant to store precise temperature measurements?

ArrayList<Double> myTemps = new ArrayList<Double>();

How do you create an ArrayList of Strings?

ArrayList<String> list = new ArrayList<String>();

What is one of the primary differences between an ArrayList and an Array?

Arrays have a fixed number of values, while ArrayLists can change in size.

Consider the following correct implementation of the selection sort algorithm: public static ArrayList<Integer> selectionSort(ArrayList<Integer> arr) { int currentMinIndex; //Line 3 int counter = 0; for (int i = 0; i < arr.size() - 1; i++) //Line 5 { currentMinIndex = i; for (int j = i + 1; j < arr.size(); j++) { if(arr.get(j) < arr.get(currentMinIndex)) //Line 10 { currentMinIndex = j; } } if (i != currentMinIndex) //Line 16 { int temp = arr.get(currentMinIndex); arr.set(currentMinIndex, arr.get(i)); //Line 19 arr.set(i, temp); } } return arr; }

Change Line 10 to if(arr.get(j) > arr.get(currentMinIndex))

A field of computer science that's related to keeping data private and secure called

Cybersecurity

True or False: Attempting to add an int or double primitive value to an ArrayList will result in an error.

False

True or False: Enhanced for loops should not be used to traverse ArrayLists.

False

True or False: Linear Search becomes more efficient as more values are added to a particular data set.

False

Some good and practical ways to avoid a phishing attempt are to I. Not click through any links in an email that seem suspicious II. Not download any attachments in an email that seem suspicious III. Not use email services at all IV. Consider the source of each email V. Consider if the email contents sound too good to be true, like you have won a prize or something

I, II, IV and V

Which of the following are some good ways to protect your own personal data? I. Use privacy settings to limit exposure II. Review posts you are tagged in and take action if needed III. Permanently delete old social media accounts you don't use IV. Google yourself on a regular basis V. Use strong passwords Vi. Stay on sites with http://

I-V all

Question: 6 Consider the following statement: ArrayList<String> newList = /* Missing Code */ Which of the following can be replaced with /* Missing Code */ so that the statement works as intended? I. new ArrayList<String>; II. new ArrayList(); III. new ArrayList<String>();

II and III

The following segment of code is meant to remove the even numbers from an ArrayList list and print the results: int counter = 0; while(counter < list.size()) { if(list.get(counter) %2 == 0) { list.remove(counter); } counter++; } System.out.println(list.toString()); The method as written, however, is incorrect. Which ArrayList(s) list would prove that this method was written incorrectly? I.[1, 2, 3, 4, 5]II.[2, 4, 5, 6, 7]III.[2, 4, 6, 8, 10]IV.[2, 5, 6, 7, 8]

II and III

A company organizes all of its client database in order of the amount of money that the account is worth. When a new account is added, it is placed in the correct order in the database based on the worth of the account. Which classic algorithm would be best suited to perform this function?

Insertion Sort

How does insertion sort work to sort an array?

Insertion Sort sets the first index as sorted, and shifts each subsequent value into the correct position by finding the lowest value on the sorted side of the array at indices lower than the current index.

What will the following code print? ArrayList<String> list = new ArrayList<String>(); list.add("I"); list.add("love"); list.add("coding"); list.add("in"); list.add("Java"); list.remove(3); System.out.println(list.get(3));

Java

The following method is a search method intended to return the index at which a String value occurs within an ArrayList: public int search(ArrayList<String> list, String target) //Line 1 { int counter = 0; while(counter < list.size()) { if(list.get(counter).equals(target)) { return list.get(counter); } counter++; } return -1; } However, there is currently an error preventing the method to work as intended. Which of the following Lines needs to be modified in order for the method to work as intended?

Line 8 - The return should be the counter, not list.get(counter).

How does Linear Search work?

Linear Search traverses an array until the desired value is found, or until the end of the array.

What value will be printed in the console after this series of commands? Assume that the ArrayList package has been imported. ArrayList<String> names = new ArrayList<String>(); names.add("Michael"); names.add("Lebron"); names.add("Serena"); names.add("Shaq"); String firstName = names.remove(0); String secondName = names.set(0, "Venus"); names.add(2, firstName); System.out.println("Names:" + secondName + " and " + names.get(1));

Names: Lebron and Serena

Will this method correctly traverse an ArrayList and remove all multiples of 3? public void remove3s(ArrayList<Integer> array) { int counter = 0; while(counter < array.size()) { if(array.get(counter) %3 == 0) { array.remove(counter); counter++; } else { counter++; } } }

No, this method is not written correctly, as the counter in the if statement will skip the next value, as the values will shift down in the ArrayList.

Which of the following only has beneficial impacts on our society? I. Collaboration II. Communication III. Sharing of information IV. Anonymity

None of these

A website organizes its list of contributors in alphabetical order by last name. The website's new manager would prefer the contributor list to be ordered in reverse alphabetical order instead. Which classic algorithm would be best suited to complete this task?

Selection Sort

How does Selection Sort work to sort an array?

Selection Sort iterates through each index and swaps the current index with the minimum value that exists in the indices greater than the current index.

What will the following code print? ArrayList<String> list = new ArrayList<String>(); list.add("Hello"); list.add("World"); System.out.println(list[0]);

There will be a compiler error

When is it more appropriate to use Insertion Sort than Selection Sort?

When the array is already slightly sorted.

What is wrong with the following code? ArrayList<int> list = new ArrayList<int>(); list.add(1); System.out.println(list.get(0));

You cannot use int as the type in an ArrayList.

Consider the following code segment: ArrayList<String> list = new ArrayList<String>(); list.add("One"); list.add("Two"); list.add("Three"); list.add("Four"); list.add("Five"); list.add("Six"); for(int i= 0; i < list.size(); i++) { l ist.remove(i); } System.out.println(list.toString());

["Two", "Four", "Six"]

Consider the following code segment: ArrayList<Integer> nums = new ArrayList<Integer>(); nums.add(10); nums.add(20); nums.add(30); nums.add(40); nums.add(50); int x = nums.remove(3); int y = x + nums.remove(0); int z = x + y; nums.add(2, z); Which of the following represents the value of nums after the code segment has been executed?

[20, 30, 90, 50]

The following array is to be sorted biggest to smallest using insertion sort. [10, 40, 50, 30, 20, 60] What will the array look like after the third pass of the for loop?

[50, 40, 30, 10, 20, 60]

Consider the following code segment: ArrayList<Integer> nums = new ArrayList<Integer>(); i nt sum = 10; while(nums.size() <= sum) { nums.add(sum); sum--; } for(int i = 0; i < nums.size(); i++) { if(nums.get(i) %5 == 0) { nums.remove(i); } } System.out.println(nums.toString()); What is printed when the code segment is executed?

[9, 8, 7, 6]

Consider the following code segment: ArrayList<String> scales = new ArrayList<String>(); scales.add("DO"); scales.add("RE"); scales.add("MI"); scales.add("FA"); scales.add("SO"); String swap = scales.get(2); scales.remove(2); String set = scales.remove(scales.size()-1); scales.add(scales.get(0)); scales.set(0,set); scales.add(scales.size()/2, swap); Which of the following represents the value of scales after the code has been executed?

[SO, RE, MI, FA, DO]

What is the standard method used to traverse ArrayLists?

for(int index = 0; index < array.size(); index++) { array.get(index); }

What is the proper way to get the number of items in an ArrayList called list?

list.size()

Which of these method implementations would correctly insert an element into an ArrayList before every even index?

public void addEven(ArrayList<E> array, E element) { for(int index = 0; index < array.size(); index++) { if(index %2 == 0) { array.add(index, element); index++; } } }

Which of these methods will properly traverse two ArrayLists and print any index that have the same value in both ArrayLists?

public void printSharedValues(ArrayList<Integer> array1, ArrayList<Integer> array2) { int index = 0; int size; if(array1.size() > array2.size()) { size = array2.size(); } else { size = array1.size(); } while(index < size) { if(array1.get(index) == array2.get(index)) { System.out.println(index); } index++; } } public void printSharedValues(ArrayList<Integer> array1, ArrayList<Integer> array2) { int index = 0; while(index < array1.size()) { if(array1.get(index) == array2.get(index)) { System.out.println(index); } index--; } }

Protocols for data sharing on the internet are

rules and conventions for communication between network devices.