Compilare: user.cpp: In member function ‘void Trie::m_Insert(int, std::__cxx11::string, Trie::Node*)’: user.cpp:49:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (index == s.size ()) { ~~~~~~^~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:110:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.size (); ++ i) { ~~^~~~~~~~~~~ user.cpp:84:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("input", "r", stdin); ^ user.cpp:85:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("output", "w", stdout); ^