C++ 2017 Verified -

fs::path p = "/tmp/test"; if (fs::exists(p)) std::cout << "File size: " << fs::file_size(p) << '\n';

C++17 is the fifth major revision of the C++ programming language standard, formally published by ISO in December 2017. It succeeded C++14 and preceded C++20. While not as groundbreaking as C++11, C++17 delivered a substantial set of practical features aimed at improving productivity, code clarity, performance, and library usability. It removed several outdated features and continued the evolution toward a safer, more expressive language. c++ 2017

if (auto it = m.find(key); it != m.end()) // use it here // it goes out of scope fs::path p = "/tmp/test"