Compilare: user.cpp: In function ‘bool verificare(std::__cxx11::string)’: user.cpp:13:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(it<s.size()) ~~^~~~~~~~~ user.cpp:17:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s.size()>n) ~~~~~~~~^~ user.cpp:48:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(n!=s.size()) ~^~~~~~~~~~