What is the difference between stack and heap memory?
PICTURE THIS: STACK VS QUEUE
Simple meaning
Stack allocates automatic locals and frees them when the scope ends.
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 allocates automatic locals
and frees them when the scope ends.
- 2Heap allocations with new
or malloc last until delete or free.
- 3Leaks and dangling pointers
come from heap mistakes.
- 4Give an example
One tiny concrete case you can say aloud.
- 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 allocates automatic locals and frees them when the scope ends. Heap allocations with new or malloc last until delete or free.