How can I make a vector containing arrays?

I am trying to learn the bucket sort algorithum in C++ and i found the following code:

// C++ program to sort an array using bucket sort 
#include <iostream> 
#include <algorithm> 
#include <vector> 
using namespace std;

// Function to sort arr[] of size n using bucket sort 
void bucketSort(float arr[], int n)
{
    // 1) Create n empty buckets 
    vector<float> b[n];

    // 2) Put array elements in different buckets 
    for (int i = 0; i < n; i++)
    {
        int bi = n * arr[i]; // Index in bucket 
        b[bi].push_back(arr[i]);
    }

    // 3) Sort individual buckets 
    for (int i = 0; i < n; i++) sort(b[i].begin(), b[i].end());

    // 4) Concatenate all buckets into arr[] 
    int index = 0;
    for (int i = 0; i < n; i++)
        for (int j = 0; j < b[i].size(); j++)
            arr[index++] = b[i][j];
}

int main()
{
    float arr[] = { 0.897, 0.565, 0.656, 0.1234, 0.665, 0.3434 };
    int n = sizeof(arr) / sizeof(arr[0]);
    bucketSort(arr, n);

    cout << "Sorted array is \n";
    for (int i = 0; i < n; i++) cout << arr[i] << " ";
    return 0;
}

But it gives me several errors:

It seems that it wants the arrays to be dynamical in order n not to be constant. I tried to do that with:

float* b = new float[n];

or something like that; but nothing came out. Why is doing that, and how can I fix it?