Multiple Choice Questions on Arrays for Introductory CS

📚 Quick Study Guide

• 🔍 Definition: An array is a data structure that stores a collection of elements of the same data type in contiguous memory locations.
• 🧠 Indexing: Array elements are accessed using their index, starting from 0 in most programming languages. For an array of size $n$, the valid indices range from $0$ to $n-1$.
• 🧮 Declaration: Arrays are typically declared with a specific data type and size, e.g., `int arr[10];` in C++ declares an integer array of size 10.
• 💾 Memory Allocation: Arrays are stored in contiguous memory blocks, enabling efficient access to elements.
• ➕ Operations: Common array operations include accessing elements, insertion, deletion, searching, and sorting.
• 💡 Applications: Arrays are used extensively in various algorithms and data structures, such as stacks, queues, matrices, and hash tables.
• ⏱️ Time Complexity: Accessing an element in an array by its index has a time complexity of $O(1)$, making it very efficient.

🧪 Practice Quiz

1. Question 1: What is the index of the first element in an array?
   1. A. 1
   2. B. 0
   3. C. -1
   4. D. Array Size
2. Question 2: Which of the following is NOT a valid operation on an array?
   1. A. Accessing an element
   2. B. Inserting an element at a specific index
   3. C. Changing the data type of elements after declaration
   4. D. Deleting an element
3. Question 3: What is the time complexity of accessing an element in an array given its index?
   1. A. $O(n)$
   2. B. $O(log n)$
   3. C. $O(1)$
   4. D. $O(n^2)$
4. Question 4: In most programming languages, how is an array stored in memory?
   1. A. Randomly
   2. B. Non-contiguously
   3. C. Contiguously
   4. D. As a linked list
5. Question 5: What is the purpose of declaring the size of an array?
   1. A. To specify the maximum number of elements it can hold
   2. B. To define the data type of the elements
   3. C. To allocate memory for the array
   4. D. All of the above
6. Question 6: Which data structure can be implemented using arrays?
   1. A. Linked List
   2. B. Queue
   3. C. Tree
   4. D. Graph
7. Question 7: What happens if you try to access an array element with an index that is out of bounds?
   1. A. The program will crash
   2. B. It will return a default value
   3. C. It will access memory outside the array's allocated space, leading to undefined behavior
   4. D. The array will automatically resize