Stack Data Structure

A stack is a linear data structure where insertion and removal happen at the same end, called the top. It follows Last-In, First-Out (LIFO) order.

This means the last item placed into the stack is the first item removed.

A common real-world example is a stack of plates. The newest plate placed on top is usually the first one taken off.

Basic Stack Operations

Overflow and Underflow

• Overflow happens when an item is pushed into a stack that has no more available space.
• Underflow happens when a pop operation is attempted on an empty stack.

In Java, built-in dynamic collections can grow as needed, but the concepts still matter when stacks are implemented with fixed-size arrays.

Java Stack lastElement()

In Java, a Stack object can use lastElement() to retrieve the item at the last index of the stack's internal list.

Syntax:

stack.lastElement();

This returns a value but does not remove it.

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