Programming

C++ Interview Prep - Programming

This C++ Interview Prep test evaluates your mastery of lambda syntax, capture mechanisms, closures, and functional programming techniques in C++.

Duration

Complete at your own pace or within the time limit

Questions

Multiple choice with one correct answer

Accuracy

Expert-reviewed questions with clear answer keys

Results

Instant detailed breakdown by topic area

Cpp - Lambda Expressions
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About This Test

This test evaluates your proficiency with lambda expressions and their use in modern C++ functional programming.

The test measures your understanding of lambda syntax, capture lists (by value, by reference), closure behavior, generic lambdas, and lambda type deduction. You'll demonstrate knowledge of using lambdas with STL algorithms and callbacks.

Questions range from basic lambda syntax and capture semantics to complex scenarios with nested lambdas, mutable captures, and std::function usage. Test cases explore capture lifetime issues and performance implications.

Analyze results to strengthen understanding of capture semantics and functional patterns. Study failed scenarios thoroughly, then refactor code using lambdas to develop practical skills in writing clean, expressive C++ code.

C++ Interview Topics You Will Face

Memory and Ownership Questions

Expect deep dives on the stack versus the heap, smart pointer selection, dangling references, and how RAII guarantees cleanup during exceptions.

The Big Five and Copy Semantics

Interviewers ask you to implement copy and move constructors, explain the rule of five, and reason about when the compiler generates them.

Templates and the STL

Be ready to write generic functions, explain iterator categories, and choose the right container based on complexity guarantees.

Undefined Behavior Traps

Classic questions probe uninitialized memory, iterator invalidation, integer overflow, and object slicing that catch out unprepared candidates.

Sample Questions

A few real questions from this test, with answers and explanations. Take the full test above for the complete set.

Where are local variables of automatic storage duration typically allocated?

Answer: On the stack

Local (automatic) variables live on the stack and are automatically freed when their scope ends. Heap allocation happens explicitly via new or allocators.

What is the vtable in C++?

Answer: A per-class table of function pointers used to dispatch virtual function calls at run time

The vtable is a per-class array of pointers to the class's virtual functions. Each polymorphic object holds a hidden pointer to its class vtable, enabling dynamic dispatch of virtual calls.

Why should a base class intended for polymorphic use declare a virtual destructor?

Answer: So that deleting a derived object through a base pointer runs the correct derived destructor

Without a virtual destructor, deleting a derived object through a base pointer is undefined behavior and typically skips the derived destructor, leaking resources. A virtual destructor ensures the full chain runs.

What does std::move actually do?

Answer: It casts its argument to an rvalue reference, enabling move operations to be selected

std::move performs no movement itself; it is an unconditional cast to an rvalue reference, signaling that the object may be moved from so overload resolution can pick a move constructor or move assignment.

Which statement about references versus pointers is correct?

Answer: A reference must refer to a valid object at initialization, whereas a pointer can be null and reassigned

A reference must be bound to an object when created and cannot be rebound or made null in well-defined code. A pointer can be null, reassigned, and supports arithmetic.

Frequently Asked Questions

Find answers to common questions about this assessment

Slicing happens when you assign a derived object to a base object by value, copying only the base part and discarding derived data and virtual behavior. Store polymorphic objects through references or pointers, ideally smart pointers, to preserve the full object.

If you delete a derived object through a base pointer and the base destructor is not virtual, only the base destructor runs, leaking derived resources. Declaring the base destructor virtual ensures the correct destructor chain executes.

RVO lets the compiler construct a returned object directly in the caller storage, eliminating the copy or move entirely. Because of it, returning by value from a function is efficient and idiomatic, so you should not return by pointer just to avoid copies.

Choose std map when you need keys kept in sorted order or need ordered range iteration, accepting logarithmic operations. Choose unordered map for average constant time lookups when order does not matter and a good hash exists.

Scores are based on the number of correct answers divided by total questions, with a breakdown by topic category.

Yes, questions are randomly selected and ordered from our question bank to ensure each attempt is unique.

No account is required. You can take the test immediately. Optionally provide an email to save your results.

There is no pass/fail threshold. The test measures your knowledge level and provides detailed feedback for improvement.

For knowledge tests, we recommend answering without external help to get an accurate assessment. Practice exercises are designed for learning, so references are acceptable.

Our questions are written for structured educational practice and can give a useful snapshot of your current knowledge in the tested topics.

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