Stacks

A stack is a linear data structure that follows the LIFO principle, meaning that the last element added to the stack is the first one to be removed. Think of it as a stack of plates: we add new plates on top, and when we need a plate, we take the top one off first. Stacks are used in various applications, including expression evaluation, function call management, and undo mechanisms in software.

Stacks have several defining characteristics that influence their behavior and performance:

• LIFO order: The last element inserted into the stack is the first one to be removed. For example, if we push the numbers 1, 2, and 3 onto a stack, we will pop them off in the reverse order: 3, 2, 1.
• Operations performed at one end: All insertions (push) and deletions (pop) are performed at the top of the stack. There is no direct access to elements in the middle or bottom of the stack. If we push several elements onto a stack, we can only access the most recently added element directly...