int
compare_function(const void* a, const void* b)
{
    return (*(int*)a - *(int*)b);
}

void
qsort_floats(floats* xs)
{
    // TODO: call qsort to sort the array
    // see "man 3 qsort" for details
    float* float_array;
    int size = sizeof(float_array)/ sizeof(float_array[0]);
    for (int i = 0; i < xs->size; ++i) {
        float_array[i] = xs->data[i];
    }

    qsort(float_array, size, sizeof(float), compare_function);
}