How to skip nan numbers in txt file

Newbie
7 
{
  Double_t x[] = {1., TMath::QuietNaN(), 3., TMath::SignalingNaN(), 5.};
  for (unsigned i = 0; i < sizeof(x) / sizeof(Double_t); i++) {
    if (TMath::Finite(x[i])) cout << x[i] << endl;
    else cout << "it's a lulu" << endl;
  }
}