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Queue Visualizer — Enqueue & Dequeue (FIFO)

Interactive FIFO queue — enqueue and dequeue with animated front/rear pointers and step controls. Runs in your browser.

Free No signup Client-side Privacy friendly Updated

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Pseudocode

Run an operation to see its steps.

How to use

  1. 1 Type a number and press Enqueue to add it at the rear of the queue.
  2. 2 Press Dequeue to remove the element at the front (first in, first out).
  3. 3 Use Random to enqueue a random value, or Clear to empty the queue.
  4. 4 Step back and forward through any operation.

Why use this tool

  • See the FIFO rule: the first value enqueued is the first one dequeued.
  • Watch the "front" and "rear" pointers as the queue grows and shrinks.
  • Understand why enqueue and dequeue are O(1).
  • Runs entirely in your browser. No signup, no uploads.

Frequently asked questions

What is a queue?

A queue is a FIFO (first-in, first-out) collection: elements are added at the rear (enqueue) and removed from the front (dequeue).

What is the time complexity of queue operations?

Enqueue and dequeue are O(1) with the right implementation (a linked list or a circular buffer).

What are queues used for?

Task scheduling, breadth-first search, buffering, print spooling, and any first-come-first-served processing.

What is a circular queue?

A queue implemented on a fixed-size array whose front and rear indices wrap around, reusing freed slots without shifting elements.

What is Queue Visualizer?

A Queue Visualizer animates a queue — a first-in, first-out (FIFO) collection where values are added at the rear (enqueue) and removed from the front (dequeue). Both operations are O(1).

Features

Enqueue / dequeue / peek

Animate elements entering at the rear and leaving from the front.

Complexity

enqueue / dequeue / peek: O(1) each. Space: O(n). FIFO order.

100% private

Runs entirely in your browser — nothing is uploaded.

Example

Input

enqueue A, enqueue B, enqueue C, then dequeue

Output

dequeue → A (FIFO: first in, first out)

Common use cases

  1. 1

    Understand FIFO

    See why the first element added is the first removed.

  2. 2

    Scheduling & buffering

    Relate queues to task scheduling, print spools, and buffers.

  3. 3

    BFS building block

    Learn the queue that drives breadth-first search.

Summary

Zerethon's queue visualizer animates a FIFO (first-in, first-out) queue in your browser, showing enqueue, dequeue, and peek. Every queue operation runs in O(1) time; space is O(n) for n elements. The earliest element added is always the first one removed.

Category
Algorithm
Pricing
Free
Privacy
Browser-based
Signup
Not required

References

Privacy

Your data never leaves your browser unless explicitly stated. Queue Visualizer runs entirely client-side — no server upload, no logging, no tracking of your input.

New to this? Read the step-by-step explanation with Big-O analysis: Learn Data Structures →

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