Stack & Queue • Concepts

Front and Rear Pointers

Unlike Stacks which only need a single 'Top' pointer, Queues require two distinct pointers to manage their First-In-First-Out nature.

The Front Pointer

Points to the element that was added first (the oldest element). This is where all `Dequeue` operations occur. When you dequeue, the Front pointer moves forward.

The Rear Pointer

Points to the element that was added last (the newest element). This is where all `Enqueue` operations occur. When you enqueue, the Rear pointer moves forward.

Pointer Lifecycle

In a newly initialized array queue, both pointers usually start at `-1`. When the first item is added, both jump to `0`. If Front overtakes Rear (`Front > Rear`), the queue has become completely empty.

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Stack & Queue • Concepts

Front and Rear Pointers

Unlike Stacks which only need a single 'Top' pointer, Queues require two distinct pointers to manage their First-In-First-Out nature.

The Front Pointer

Points to the element that was added first (the oldest element). This is where all `Dequeue` operations occur. When you dequeue, the Front pointer moves forward.

The Rear Pointer

Points to the element that was added last (the newest element). This is where all `Enqueue` operations occur. When you enqueue, the Rear pointer moves forward.

Front And Rear

Front And Rear

Front and Rear Pointers

The Front Pointer

The Rear Pointer

Pointer Lifecycle

Front and Rear Pointers

The Front Pointer

The Rear Pointer

Pointer Lifecycle