int bitcount(int n) {
    unsigned int c1 = 0;
    for (; n > 0; n >>= 1)
        if (n & 1) {
            c1++;
        }
    return c1;
    }

int main() {
    int a = -2;
    printf("%u n", bitcount(a));
    return 0;
    }

int bits(unsigned int x)
{
    x = x - ((x >> 1) & 0x55555555);
    x = (x & 0x33333333) + ((x>>2)&0x33333333);
    x = (x + (x >> 4)) & 0x0F0F0F0F;
    x += x >> 8;
    x += x >> 16;
    return x&0x3F;
}

int main()
{
    for(int i = -5; i <= 5; ++i)
        cout << setw(3) << i << setw(6) << bits(i) << endl;
}