Date: 2025apr3 Language: C++ Q. C++: get the extension/suffix of filename A. With C++17 or later use std::filesystem like this

#include <filesystem> std::string extension(const std::string absfilename) { if (absfilename.empty()) return ""; std::string s = std::filesystem::path(absfilename).extension(); if (s[0] == '.') { s = s.substr(1); } // String it normally begins with the dot return s; }