int luhn(const char* cc)
{
	const int m[] = {0,2,4,6,8,1,3,5,7,9}; 
	int i, odd = 1, sum = 0;

	for (i = strlen(cc); i--; odd = !odd) {
		int digit = cc[i] - '0';
		sum += odd ? digit : m[digit];
	}

	return sum % 10 == 0;
}

int main()
{
	const char* cc[] = {
		,
		,
		,
		,
		0
	};
	int i;

	for (i = 0; cc[i]; i++)
		printf(, cc[i], luhn(cc[i]) ?  : );

	return 0;
}