static string
contingency_table(const Vectors& v, int variable1, int variable2,
const string& filename, int iformat)
{
StatError error;
std::stringstream s;
bool ret;
output_format format = output_format(iformat);
ret = v.contingency_table(error, s, variable1, variable2, filename.c_str(),
format);
if (!ret)
stat_tool::wrap_util::throw_error(error);
return s.str();
}
