Stack: What Does "Last-In-First-Out" Mean? Principle Diagram

This article uses "stacking plates" as an example to explain the core concepts of the data structure "stack". A stack is a linear list where insertions and deletions can only be performed from one end (the top), with the other end being the bottom. Its core feature is "Last-In-First-Out" (LIFO) — the last element added is the first to be removed. Basic operations of a stack include: push (adding an element to the top), pop (removing and returning the top element), top (viewing the top element), and empty (checking if the stack is empty). For example, when stacking plates, new plates are placed on top (push), and the top plate must be taken first (pop), which aligns with LIFO. Stacks are widely applied in life and programming: bracket matching (using the stack to record left brackets, popping to match right brackets), function call stacks (functions called later return first), and browser back functionality (successively popping recently visited webpages). Understanding the "LIFO" feature of stacks helps solve problems like recursion and dynamic programming, making it a foundational tool in data structures.