int main() {
try {
Student_info record;
record.grade();
} catch (domain_error e) {
cout << e.what() << endl;
}
return 0;
}
double grade_aux(const Student_info& s)
{
return s.grade();
}
bool fgrade(Student_info& s)
{
return s.grade() < 60;
}
int main() {
Student_info record;
if (record.valid()) record.grade();
return 0;
}