Compilare: main.cpp: In member function 'void Trie::insert(const string&)': main.cpp:35:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < key.size();++i){ ~~^~~~~~~~~~~~ main.cpp: In member function 'int Trie::numar_aparitii(const string&)': main.cpp:52:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < key.size();++i){ ~~^~~~~~~~~~~~ main.cpp: In member function 'int Trie::prefix_comun(const string&)': main.cpp:68:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < key.size();++i){ ~~^~~~~~~~~~~~ main.cpp: In member function 'bool Trie::searchString(const string&)': main.cpp:94:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < key.size();++i){ ~~^~~~~~~~~~~~ main.cpp: In member function 'void Trie::deleteString(std::__cxx11::string)': main.cpp:111:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < key.size();++i){ ~~^~~~~~~~~~~~