C语言二进制转换问题

请问这道题目应该怎么做呀？我不太理解，123456789987654321(凑字数)

int fun(int n)
{
    int a = 0, b = 0;
    while (n)
    {
        if (n % 2 == 1)
            a++;
        else
            b++;
        n /= 2;
    }
    return a > b;
}

int main()
{
    int k1, k2, nA = 0, nB = 0;

    scanf("%d%d", &k1, &k2);
    while (k1 <= k2)
    {
        if (fun(k1))
            nA++;
        else
            nB++;

        k1++;
    }
    printf("%d %d", nA, nB);

    return 0;
}