All Flashcards
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
list.add("apple");
list.add("banana");
System.out.println(list.size());
2
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(10);
list.add(20);
list.set(0, 15);
System.out.println(list.get(0));
15
Identify the error in the following code:
java
ArrayList<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
System.out.println(list.get(2));
IndexOutOfBoundsException: The index 2 is out of bounds for the list of size 2.
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
list.add("A");
list.add("B");
list.remove(0);
System.out.println(list.size());
1
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(5);
list.add(10);
list.add(5);
int index = list.indexOf(5);
System.out.println(index);
0
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
System.out.println(list.size());
0
Identify the error in the following code:
java
ArrayList<int> list = new ArrayList<>();
ArrayLists cannot store primitive types directly. Use the Integer wrapper class instead: ArrayList
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
list.add(3);
list.clear();
System.out.println(list.size());
0
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
list.add("apple");
list.add("banana");
System.out.println(list.get(1));
banana
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(5);
list.add(10);
list.remove(Integer.valueOf(5));
System.out.println(list.size());
1
What are the differences between ArrayLists and arrays?
ArrayLists: Dynamic size, use methods | Arrays: Fixed size, use bracket notation
What are the differences between selection sort and insertion sort?
Selection Sort: Finds minimum and swaps | Insertion Sort: Inserts elements into correct position
What are the differences between using a for loop and a for-each loop to traverse an ArrayList?
For loop: Uses index, can modify | For-each loop: No index, cannot modify
What are the differences between add(E obj) and add(int index, E obj) in ArrayLists?
add(E obj): Appends to the end | add(int index, E obj): Inserts at a specific index
What are the differences between get(int index) and set(int index, E obj) in ArrayLists?
get(int index): Retrieves element at index | set(int index, E obj): Updates element at index
What are the differences between using primitive types and wrapper classes in ArrayLists?
Primitive types: Cannot be stored directly | Wrapper classes: Can be stored in ArrayLists
What are the differences between searching and sorting?
Searching: Locates a specific element | Sorting: Arranges all elements in order
What are the differences between arrays and ArrayLists in terms of memory usage?
Arrays: Allocate fixed memory | ArrayLists: Dynamically allocate memory, potentially more overhead
What are the differences between the best-case time complexity of selection sort and insertion sort?
Selection Sort: O(n^2) | Insertion Sort: O(n)
What are the differences between the worst-case time complexity of selection sort and insertion sort?
Selection Sort: O(n^2) | Insertion Sort: O(n^2)
How is ArrayList used in real-world scenarios?
Storing a list of customers in a database or managing a playlist of songs.
How is linear search applied in real-world scenarios?
Finding a specific product in a small inventory list.
How is selection sort applied in real-world scenarios?
Sorting a small list of student names alphabetically.
How is insertion sort applied in real-world scenarios?
Sorting a hand of cards as you receive them in a card game.
How is encryption used to protect user data?
Securing online transactions and protecting sensitive information from hackers.
Give a real-world example of ethical data collection.
A research study that obtains informed consent from participants before collecting their data.
How are ArrayLists used in social media applications?
Storing lists of friends, posts, or comments.
How are ArrayLists used in e-commerce applications?
Managing shopping carts and product lists.
How is data collection used in healthcare?
Tracking patient health records and monitoring disease outbreaks.
How is data collection used in education?
Tracking student performance and personalizing learning experiences.