What does ‘underflow’ mean in a Queue?

Java MCQ: What does ‘underflow’ mean in a Queue?

Answer:

Explanation:

‘Underflow’ in a queue refers to a situation where an attempt is made to remove an element from an empty queue. Since the queue is empty, there are no elements to dequeue, leading to an underflow condition. This is an error state, similar to trying to pop an element from an empty stack.

Underflow can occur in both static and dynamic queues. In a static queue (e.g., an array-based implementation), underflow occurs when the front pointer exceeds the rear pointer, indicating that all elements have been dequeued. In a dynamic queue (e.g., a linked list-based implementation), underflow occurs when the queue is empty, and there are no nodes to remove.

Here’s an example of handling queue underflow in Java:

import java.util.LinkedList;
import java.util.Queue;

public class Main {
    public static void main(String[] args) {
        Queue<Integer> queue = new LinkedList<>();
        try {
            int frontElement = queue.remove(); // Attempt to dequeue from an empty queue
        } catch (Exception e) {
            System.out.println("Queue underflow occurred.");
        }
    }
}

In this example, attempting to remove an element from an empty queue throws an exception, which is caught and handled. Proper error handling is essential to avoid crashes and ensure the robustness of programs that use queues, especially in applications where dynamic data handling is involved.

Reference links:

https://www.javaguides.net/p/java-queue-tutorial.html