Compilare: user.cpp: In function ‘void parse(std::ifstream&, std::vector<std::vector<std::basic_string<char> > >&)’: user.cpp:13:10: warning: unused variable ‘ch’ [-Wunused-variable] char ch; ^ user.cpp: In function ‘int main()’: user.cpp:89:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<csv.size(); i++) ^ user.cpp:91:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<csv[i].size(); j++) ^