Queue Visualizer (FIFO)

Interactive queue data-structure visualizer — enqueue at the tail, dequeue from the head, peek the front.

Value

Queue state

Dequeue (head) Enqueue (tail)

Size

Front (head)

—

Rear (tail)

—

Operations

Step log

Type a value (number or text) and press Enter or click Enqueue to append it at the tail. Dequeue removes and returns the head; Front peeks the head without removing; Clear empties the queue. The HEAD and TAIL badges mark the two ends, and the step log records every operation with a timestamp.

Where queues are used

Task scheduling

OS ready queues and printer spoolers serve requests in arrival order — fair and starvation-free for equal-priority tasks.

Breadth-first search

BFS over graphs and trees uses a queue to visit nodes level by level, yielding the shortest path on unweighted graphs.

Buffers & pipelines

Producer/consumer pipelines, IO buffers and message queues decouple stage speeds — data leaves in the order it arrived.