Summary

A stack stores items with last_in_first_out order. Use push to add to the top, pop to remove the top, and peek to read the top without removing. Check emptiness with is_empty and count items with size. Removing from an empty stack is underflow; adding beyond capacity is overflow. Stacks appear in function_calls, recursion, undo_redo, and expression_parsing. Remember: the most recently pushed item is the first one popped.