Compilare: user.cpp: In member function ‘void Trie::remove(std::string&)’: user.cpp:56:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] next = ++l < word.size() ? cur->children[word[l]] : NULL; ^ user.cpp: In function ‘int main()’: user.cpp:100:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( IA_PROB".in", "r", stdin ); ^ user.cpp:101:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( IA_PROB".out", "w", stdout ); ^ user.cpp:106:26: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets( line, 32, stdin ); ^ user.cpp:121:27: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets( line, 32, stdin ); ^