n % 10Only the number on the number is taken each time.
Such as:1234 % 10 = 4;1234 / 10 = 123;123 % 10 = 3…
private static boolean cheak(int n) {
while (n != 0) {
int a = n % 10;
if (a == 2 || a == 0 || a == 1 || a == 9) {
return true;
}
n /= 10;
}
return false;
}