//тест & для целых переменных
void can_bit_and() {
    for (int i = 0; i < 1000; i++) {
        int c = i & (i + 2);
        assert(bit_and_for_int_f1(i, i + 2) == bit_and_for_int_f2(i, i + 2));
        assert(c == bit_and_for_int_f1(i, i + 2));
        assert(c == bit_and_for_int_f2(i, i + 2));
    }
}