Interview essentials

Last reviewed May 28, 2026 Content v20260528

Track mode: server_compiled
Means: Compiled runner
Reading: ~2 min
Level: advanced

This lesson

A recap and interview lens on Interview essentials—connecting earlier C++ lessons to systems and native-code expectations.

Interviewers expect RAII, rule of three/five, STL complexity, and when modern C++ beats C—not just syntax.

You will apply Interview essentials in contexts like: Game engines, trading systems, desktop apps, and performance-critical libraries.

Write C++ in main.cpp with int main(), click Run on server—the dev runner compiles with c++/g++ -std=c++17 -Wall and runs the binary; read template errors in stderr (LEARNING_RUNNER_ENABLED=true). Also read the interview prep blocks.

When earlier lessons and MCQs feel comfortable, or when you are interviewing for systems, embedded, or native roles.

C++ interviews focus on OOP, memory, STL, move semantics, templates, and modern best practices. Be ready to explain trade-offs with Java GC, C manual memory, and Rust ownership.

Must-know topics

RAII, constructors/destructors, rule of zero/five
virtual functions, vtables, abstract classes
STL containers, iterators, algorithms
Smart pointers, move semantics, lvalue/rvalue references
Templates vs runtime polymorphism
const correctness, exceptions, compilation model

Important interview questions and answers

Q: Explain RAII in 30 seconds.
A: Acquire resources in constructors; release in destructors tied to scope—exceptions still unwind and cleanup runs.
Q: unique_ptr vs shared_ptr?
A: Exclusive ownership vs reference-counted sharing; default to unique_ptr.
Q: When not use C++?
A: Simple CRUD web apps, teams without C++ expertise, or domains where managed languages dominate and native latency is unnecessary.

Self-check

List three C++ topics you will review before interviews.
How does error handling differ from Java exceptions in style debates?

Tip: Be ready to whiteboard RAII, virtual destructors, and unique_ptr vs shared_ptr—common screen questions.

Interview prep

Must-know C++ interview topics?: RAII, OOP/virtual, STL, smart pointers, move semantics, templates, const correctness, and compilation model.
Explain RAII in 30 seconds?: Acquire resources in constructors; release in destructors at scope end—works with exceptions via stack unwinding.

Interview tip Lesson completion confidence

Can you explain this lesson in 30 seconds without reading notes?

Self-reflection (saved on this device)

Not saved yet.

Playground

Runs on the configured server runner (dev: npm run runner with LEARNING_RUNNER_ENABLED=true). Output appears below the editor.

Code runner not available

Server runner is disabled. Set LEARNING_RUNNER_ENABLED=true and LEARNING_RUNNER_URL in .env (see .env.example).

Check yourself

Multiple choice — immediate feedback.

Discussion

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Starter discussion topics

Weakest C++ topic?
RAII 30s explain?

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