Stack • Core Implementation

Stack using Linked List

Implementing a Stack with a Linked List removes the fixed-size limitation of arrays. Memory is allocated dynamically on the heap for each push.

The Top Pointer

Instead of an integer index, `top` is a memory pointer that references the Head node of a Singly Linked List.

Pushing to a Stack is equivalent to "Insert at Beginning" in a Linked List. `newNode.next = top`, and then `top = newNode`.

Popping is equivalent to "Delete from Beginning". You save the value, and simply move the pointer: `top = top.next`.

Stack is Empty (Top = NULL)

Code Tracker

:::

1function push(val) {

2 let newNode = new Node(val);

3 newNode.next = top;

4 top = newNode;

5}

6function pop() {

7 if (top === null) return 'Underflow';

8 let val = top.val;

9 top = top.next;

10 return val;

11}