Compilare: user.cpp: In function ‘int main()’: user.cpp:56:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0,y;i<s.size();++i) ^ user.cpp:59:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<s.size() && isdigit(s[i])) ^ user.cpp:68:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<prim.size();++i) ^ user.cpp:80:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<prim.size();++i) ^