This is how you validate a QR reference number, which was formerly known as ISR reference number (inpayment slip with reference number).
#include <iostream>
#include <qrinvoice/util/qr_reference_util.hpp>
// ...
std::cout << qrinvoice::qr_reference_util::is_valid_qr_reference("11 00012 34560 00000 00008 13457") << std::endl;
std::cout << qrinvoice::qr_reference_util::is_valid_qr_reference("110001234560000000000813457") << std::endl;
// prints 1 (true)
std::cout << qrinvoice::qr_reference_util::is_valid_qr_reference("11 00012 34560 00000 00008 13456") << std::endl;
// prints 0 (false), due to wrong checksumThis is how you validate a structured creditor reference (ISO 11649) using the creditor_reference_util functions.
#include <iostream>
#include <qrinvoice/util/creditor_reference_util.hpp>
// ...
std::cout << "creditor_reference_valid: " << qrinvoice::creditor_reference_util::is_valid_creditor_reference("RF45 1234 5123 45") << std::endl;
// prints 1 (true)