All different digit

bool alldiff(int n) {
    int c, mask = 0;
    for (int i = 0; i < 5; i++) {
        c = (int) (n / pow(10, i)) % 10;
        if ((mask >> c) % 2)
            return false;
        mask |= 1 << c;
    }
    return true;
}