Factor

#include<stdio.h>
#include<stdlib.h>
#include<math.h>

typedef  int BitArray_t[];

#define int_size sizeof(int)

#define size(x) x[0] * bits

#define bits int_size * 8

#define div(pos) pos / (bits)

#define mod(pos) pos % (bits)

#define create(x, amount)   int b_array_size = amount / (bits);\
                                if (amount % (bits)) b_array_size++;\
                                int x[b_array_size + 1];\
                                for(int i = 0; i <= b_array_size; i++) x[i] = 0;\
                                x[0] = b_array_size

#define GET_BIT_(x, position) (((x[div(position) + 1]) & ((int)1 << mod(position))) != 0)


#define SET_BIT_(x, position, val) if (val) (x[div(position) + 1] |= ((int)1 << (mod(position))));\
                                       else (x[div(position) + 1] &= ~((int)1 << (mod(position))))

int main(int argc, char **argv)
{

    int c = atoi(argv[1]);
    const int SC = (int)sqrt(c);
    create(b_array, c);

    for (int i = 2; i < SC; i++)
    {
        if (!(GET_BIT_(b_array,i)))
        {
            for (int j = 2; j * i < size(b_array); j++)
            {
                SET_BIT_(b_array, j * i, 1);
            }
        }
    }

    int i = 2;

    if (c)
    {
        while (c != 1)
        {
            if ((!(GET_BIT_(b_array, i))) && !(c % i))
            {
                printf("%d ", i);
                c /=i;
            }
            else
                i++;
        }
    }
}