Compilare: user.cpp: In function ‘int factor(int, std::vector<int>)’: user.cpp:68:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j<func[i].size() && '0'<=func[i][j] && func[i][j]<='9') ^ user.cpp: In function ‘int main()’: user.cpp:133:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < str.size()) func[str[0]-'A'].push_back(str[j]) , ++j; ^ user.cpp:136:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<str.size();++j) ^ user.cpp:145:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j<str.size()) ^