Stack • Core Operations

The Pop Operation

Popping is the act of removing and returning the element currently at the top of the Stack. Like Push, it runs in O(1) constant time.

Step 1: Check Underflow

Always verify if `IsEmpty()` is true. If the stack is empty (`top === -1`), popping will cause a memory violation (Underflow).

Read the value at `stack[top]` and store it in a temporary variable so you can return it to the caller later.

Decrement the `top` pointer by 1. In C/C++, you don't even need to overwrite the old data! Just moving the pointer is enough to "delete" it.

Stack (Size 5)

10

20

30

◀Top: 2

Popped Value

-

Code Tracker

:::

1function pop() {

2 if (top === -1) {

3 console.log('Stack Underflow');

4 return null;

5 }

6 let val = stack[top];

7 top--;

8 return val;

9}