📚 Stack Class Overview

🎯 Purpose

The Stack class is designed to:

• Store elements in a Last-In-First-Out (LIFO) order.
• Provide operations to push, pop, and peek elements.

🔑 Key Features

🧱 Node Structure:

Each Node contains:

• A value (val) of type Object.
• A reference to the next node (next).

🧩 Attributes:

• top: Points to the top node of the stack.

🛠️ Methods:

• push(Object v)

  Adds a new element to the top of the stack.

  Creates a new Node and updates the top reference.

• pop()

  Removes and returns the top element of the stack.

  Throws a RuntimeException if the stack is empty.

• peek()

  Returns the top element without removing it.

  Throws a RuntimeException if the stack is empty.

• isEmpty()

  Returns true if the stack is empty, otherwise false.