Stack & Queue Implementations (Array and Linked List)

This project implements stack and queue data structures in Java using both array-based and linked-list–based approaches. All core data structures are implemented from scratch, without using Java’s built-in Stack, Queue, or LinkedList classes, to demonstrate a deep understanding of underlying data structure mechanics.

The program provides a menu-driven console interface that allows users to interactively add, remove, and inspect data across multiple stack and queue implementations.

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✨ Features

• Stack implementation using an array
• Stack implementation using a linked list
• Queue implementation using a circular array
• Queue implementation using a linked list
• Custom linked list and node implementation
• Menu-driven interface for interactive testing
• Ability to compare behavior across implementations

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🛠️ Technologies Used

• Java
• Object-Oriented Programming
• Custom data structure implementations

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📁 Project Structure

.
├── StackQueueDemo.java      # Main program (menu-driven interface)
├── StackArray.java          # Stack implemented using an array
├── StackList.java           # Stack implemented using a linked list
├── QueueArray.java          # Circular queue implemented using an array
├── QueueList.java           # Queue implemented using a linked list
├── Node.java                # Node implementation for linked lists
├── SampleData.java          # Sample data generator
└── README.md

🧠 Design Notes

• No built-in stack, queue, or linked list data types are used
• Linked lists are implemented manually using a custom Node class
• The array-based queue uses a circular buffer to optimize space
• This design enables direct comparison of:
  • Memory usage patterns
  • Insertion/removal behavior
  • Structural differences between implementations

🧪 Build & Run Compile all files:

javac *.java

Run the program:

java StackQueueDemo

📜 License

This project is licensed under the MIT License. See the LICENSE file for details.

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👤 Author

Hannah G. Simon