The IBAN consists of up to 34 alphanumeric characters, comprising a country code, two check digits and a long and detailed bank account-number. The check digits enable a sanity check of the bank account number to confirm its integrity before submitting a transaction.he Basic Bank Account Number (BBAN) format is decided by the national central bank or designated payment authority of each country. There is no consistency between the formats adopted. The national authority may register its BBAN format with SWIFT, but is not obliged to do so. It may adopt IBAN without registration.
You can detect at compile time if a type is an interface with __is_interface_class(type) . For more information, see Compiler Support for Type Traits (C++ Component Extensions) .
In my opinion: 1  static methods do not belong to interfaces. They belong to utility classes.  2 default methods shouldn't have been allowed in interfaces at all. You could always use an abstract class for this purpose.