static void Main(string[] args) { do { int n; n = SoNguyen.NhapSoNguyenDuong("Nhap n="); if (TinhToan.toanchan(n)) { Console.Write(n + " toan chan"); } else { Console.Write(n + " khong toan chan"); } } while (SoNguyen.NhapSoNguyen("\nTiep tuc (1.Tiep, 0.Khong)") != 0); }