What is the difference between stack and heap?
PICTURE THIS: STACK VS QUEUE
Simple meaning
Stack holds locals and is freed when the function returns
WHY — Memory instead of guessing?
Why interviewers care about Memory:
contrast on Memory, not two memorised paragraphs.
the developer, then one case where picking wrong hurts.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1Stack holds locals and
is freed when the function returns
- 2Why it exists
it is fast and limited.
- 3Heap is new and
delete, lives until I free it, and can fragment.
- 4I keep large or
long-lived objects on the heap and small locals on the stack.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
Stack holds locals and is freed when the function returns it is fast and limited.