std::optional usagesstd::nulloptstd::optional<T>::or_elsestd::optional<T>::and_thenstd::optional<T>::transform 씹어먹는 C++ - <17 - 5. C++ 17 의 std::optional, variant, tuple 살펴보기>Copyright © 2018. Jaebum Lee. All rights reserved.https://modoocode.com/309
