Area of Improvements
Review your assessments and practice — drill into each subject, then each attempt, then each question.
Back to summary
C Programming · Round 1
Question 4 of 10
Topic: Constants & literalsDifficulty: HardBloom: Analyze
Question
How would you debug a program where a pointer dereference is failing intermittently?
Result
Knowledge
65%
Delivery
60%
Technical relevancy
68%
Technical term match
58%
Your recording
Your transcript
I would print the pointer value before using it. Maybe use gdb to step through. If it's intermittent it's probably uninitialized memory or something getting freed.
Better answer
Reproduce under a memory checker (valgrind, AddressSanitizer) to catch use-after-free, double-free, and uninitialized reads — these explain most intermittent dereference failures. Add asserts on pointer != NULL and on invariants before deref. In gdb, use watchpoints on the pointer's storage to find who mutates it, and check for stack corruption from buffer overruns nearby.
Coverage
Hit 3 of 5- Reaches for valgrind / AddressSanitizer
- Considers uninitialized memory
- Considers use-after-free
- Mentions gdb watchpoints or breakpoints
- Suggests defensive asserts on NULL/invariants
Gaps
- Did not mention sanitizers as the first-line tool
- Skipped stack corruption from adjacent buffer overruns
Misconceptions
None detected.