C++: What is std::filesystem in C++17?

1#include <filesystem>
2namespace fs = std::filesystem;
3
4// Path operations
5fs::path p = "/home/user/file.txt";
6std::cout << p.filename();  // "file.txt"
7std::cout << p.stem();     // "file"
8std::cout << p.extension(); // ".txt"
9
10// File operations
11fs::create_directories("dir/subdir");
12fs::copy("source.txt", "dest.txt");
13fs::rename("old.txt", "new.txt");
14fs::remove("file.txt");
15
16// Iteration
17for (const auto& entry : fs::directory_iterator(".")) {
18    std::cout << entry.path() << "\n";
19}
20
21// Info
22auto status = fs::status("file.txt");
23std::cout << fs::file_size("file.txt");
24std::cout << fs::exists("file.txt");