#include <stdio.h>

void swap_double(double *a, double *b) {
    double t = *a;
    *a = *b;
    *b = t;
}

void rearrange(double *arr, int n) {
    int j = 0;
    for (int i = 0; i < n; ++i) {
        if (arr[i] < 0.000001 ) {
            if (i != j)
                swap_double(&arr[i], &arr[j]);
            ++j;
        }
    }
}

int main(void)
{
    double arr[] = { -1/6.0, 2/6.0, -3/6.0, 4/3.0, 5/3.0, 6/3.0, -7/3.0, 8/3.0, 9/3.0 };
    int n = sizeof(arr) / sizeof(arr[0]);
    for (int i = 0; i < n; ++i)
        printf("%.6lf ", arr[i]);
    printf("\n");
    rearrange(arr, n);
    for (int i = 0; i < n; ++i)
        printf("%.6lf ", arr[i]);
    printf("\n");
    return 0;
}