CPP Modern C++ Features (C++17/20) 3

Question 1

What is the primary advantage of `std::string_view` over `const std::string&` as a function parameter?

Accepted Answer

Avoids copying and works with any contiguous char sequence

Answer

std::string_view is a non-owning reference to any contiguous char sequence, avoiding the potential heap allocation that const string& may trigger from C-strings.

Question 2

Which C++17 type holds exactly one value from a fixed set of types and throws `std::bad_variant_access` on wrong access?

Accepted Answer

std::variant

Answer

std::variant is a type-safe union that holds one of its listed types and throws on incorrect type access via std::get.

Question 3

What does `std::any` store differently compared to `std::variant`?

Accepted Answer

An arbitrary type not known at compile time

Answer

std::any can hold any CopyConstructible type decided at runtime, whereas std::variant requires the type set to be fixed at compile time.

Question 4

Which C++17 parallel execution policy requests that the algorithm execute with vectorization and multithreading?

Accepted Answer

std::execution::par_unseq

Answer

par_unseq permits both parallel and vectorized (SIMD) execution, imposing the most restrictions on the user's callable.

Question 5

What does the C++17 `std::filesystem::path` operator `/` do?

Accepted Answer

Appends a path component using the platform separator

Answer

operator/ on filesystem::path concatenates path components, inserting the platform's preferred separator between them.

(CPP) C++ Programming Professional Certificate Practice Test

(CPP) C++ Programming Professional Certificate Practice Test

CPP Modern C++ Features (C++17/20) 3