A stack is simple to describe — last in, first out — but to use it well you need to know what is happening underneath. Internally, a stack is just a container (commonly an array, sometimes a linked list) plus a single marker, the top, that tells you where the next item goes and which item comes off next. Every core operation is defined in terms of that marker: push writes at the top and advances it, pop reads at the top and retracts it, peek reads without changing it, and size is derived from it.
This topic matters in COP3530 because you will build a Stack class in JavaScript rather than only use one. Writing push and pop yourself forces you to confront the details that are easy to gloss over: what the top should be when the stack is empty, what happens when you pop an empty stack (underflow) or push onto a full fixed-size array (overflow), and how to keep the internal container private so callers cannot bypass LIFO ordering. The same reasoning explains why push and pop are O(1) time while the stack as a whole is O(n) space.
As you watch, track three things in every example: where the top marker sits before and after each operation, the exact order of the steps inside push and pop (check the boundary first, then move the pointer and the data), and which parts of the implementation would change if you swapped an array for a linked list. The videos below use array-based stacks in C-style pseudocode and code; your job is to carry the mechanics over to a JavaScript class.
A focused follow-up lecture on implementing the push operation using an array as the underlying container. Expect coverage of how the top index is initialized and incremented, how elements are written into the array, and the overflow condition that occurs when the array is already full. This is the clearest link between the abstract operation and a concrete container.
It directly addresses several subtopics at once — underlying data containers, the top pointer, push mechanics, and boundary conditions — in a short, exam-focused lecture from an established CS channel.
An introductory lecture on the stack as an abstract data type, presenting the LIFO principle and walking through the push and pop operations. Based on its title and description, it establishes the basic vocabulary — top, push, pop — and traces how elements enter and leave the structure. Watch this first if the idea of a single access point at the top is still new to you.
Gate Smashers produces widely used exam-oriented CS lectures, and this one sets up the conceptual model of top, push, and pop that the rest of the topic builds on before any code appears.
A step-by-step walkthrough of push and pop on an array-backed stack, presented as part of a C data structures series. The description promises a detailed trace of exactly what happens at the top during each operation, so expect the array contents and the top index to be shown changing together. It complements the earlier videos by covering pop with the same care as push.
The paired, step-by-step treatment of both operations reinforces pop mechanics and empty-stack boundary checks, which are the details students most often get wrong when writing their own class.
Together these videos support MO1 by grounding the LIFO principle in the behavior of a single top marker, and MO2 by showing the exact step order inside push and pop that you will translate into a JavaScript Stack class with peek, isEmpty, size, and toString. The array-based implementations supply the evidence for MO3: because push and pop touch only the top index, they run in constant time, and the array container makes the O(n) space cost of storing n elements visible. Understanding these internals also prepares you for MO4 and MO5, since expression-evaluation algorithms and features like undo and call stacks depend on push and pop behaving predictably at the boundaries.
These videos were chosen from YouTube on October 2, 2026. Each has captions; the player turns them on. Videos on YouTube can be changed or removed — if one no longer plays, tell your instructor. If a player does not appear, use its Watch on YouTube link.