Compilare: user.cpp: In member function ‘int Read::getNextInt()’: user.cpp:29:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (pos < s.size() && '0' <= s[pos] && s[pos] <= '9') { ~~~~^~~~~~~~~~ user.cpp: In member function ‘int Read::nextInt()’: user.cpp:39:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (pos >= s.size()) { ~~~~^~~~~~~~~~~