Compilare: user.cpp: In function 'void adauga(std::string)': user.cpp:48: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void sterge(std::string)': user.cpp:59: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'int nr_cuvinte(std::string)': user.cpp:73: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'int prefix(std::string)': user.cpp:82: warning: comparison between signed and unsigned integer expressions