Compilare: user.cpp: In function ‘int main()’: user.cpp:14:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<s.size(); i++) ^ user.cpp:18:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<s.size(); i++) ^ user.cpp:22:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(s[i]!=' ' && i<s.size()) ^