#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define INPUTLEN 27
int main() {
	char szlaszam[INPUTLEN];
	int o, i, digit, sum, cs, cc;
	int mul[] = {9, 7, 3, 1, 9, 7, 3};
	printf("GIRO számlaszám 00000000-00000000-00000000 alakban: ");
	fgets(szlaszam, INPUTLEN, stdin);
	for (o = 0; o < 19; o += 9) {
		sum = 0;
		for (i = 0; i < 7; i++) {
			digit = szlaszam[o + i] - '0';
			sum += digit * mul[i];
		}
		cs = szlaszam[o + 7] - '0';
		cc = 10 - (sum % 10);
		printf("checksum: stored =  %d vs calculated = %d -- %sVALID\n", cs, cc, ((cs == cc) ? "" : "IN"));
	}
	return 0;
}