Compilare: user.cpp: In function ‘void insereaza(std::string)’: user.cpp:29:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<s.size();i++) ^ user.cpp: In function ‘void sterge(std::string)’: user.cpp:41:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<s.size();i++) ^ user.cpp: In function ‘int query(std::string)’: user.cpp:49:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<s.size();i++) ^ user.cpp: In function ‘int prefix(std::string)’: user.cpp:60:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<s.size();i++) ^