public class LuhnVerification {
static boolean checkNumber(String value) {
int result = 0;
boolean special = false;
for (int i = value.length() - 1; i >= 0; i--) {
int v = value.charAt(i) - '0';
if (v < 0 || v > 9)
return false;
if (special) {
v = v * 2;
if (v > 9)
v = v - 10 + 1;
}
result += v;
special = !special;
}
System.out.println(result);
return result % 10 == 0;
}
public static void main(String args[]) {
System.out.println(checkNumber(""));
}
}