Queue Data Structure in C++ — Array Implementation with Enqueue, Dequeue & Menu

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A software-engineering coursework exercise: a FIFO queue built on a fixed-size array (MAX_SIZE = 10) with a console menu to try every operation.

⚙️ Operations

Function	What it does	Complexity
init()	Sets front = 0, rear = -1	O(1)
enqueue(x)	Adds x at the rear (menu checks isFull() first)	O(1)
dequeue()	Removes and returns the front element (menu checks isEmpty() first)	O(1)
size()	rear - front + 1	O(1)
isEmpty() / isFull()	Bounds checks	O(1)
display()	Prints elements front → rear	O(n)

flowchart LR
    E["enqueue → rear"] --> Q["[ front · · · rear ]"] --> D["dequeue ← front"]

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▶️ Run

g++ Untitled1.cpp -o queue
./queue

1. Enqueue
2. Dequeue
3. Size
4. Display all element
5. Quit

📚 Concepts

• FIFO (first in, first out) ordering
• Front/rear index management in a linear array
• Overflow and underflow checks

Note

This is a linear (non-circular) queue kept as a learning snapshot: slots freed by dequeue aren't reused, and the source is in its original classroom form, so it may need small fixes (explicit return types, the stray line inside main) to compile on modern compilers.

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By Intikhab Azam — AI & automation engineer

_{Keywords: queue in C++ · array implementation of queue · data structures and algorithms · enqueue dequeue · FIFO · DSA lab}