In what cases and for what purposes is the stack data structure used?

A stack is a data structure that operates on the Last In, First Out (LIFO) principle, meaning the last added element is the first to be removed.

Stacks are used when the order of processing elements in reverse to their addition is important. Examples:

• Managing function calls (call stack).
• Undo actions in applications.
• Expression processing and parsing.
• Graph and tree traversal (DFS).

In iOS, stacks are often used in navigation between screens — the last opened screen is closed first, which aligns with the stack principle.