how does radix sort work code example

Example 1: radix sort

function getDigit(num, i) {
  return Math.floor(Math.abs(num) / Math.pow(10,i)) % 10
}

function digitCount(num) {
  if(num === 0 ) return 1
  return Math.floor(Math.log10(Math.abs(num))) + 1
}

function mostDigitCount(nums) {
  let maxDigit = 0
  for(let i = 0;i< nums.length;i++) {
    maxDigit = Math.max(maxDigit, digitCount(nums[i]))
  }
  return maxDigit
}

function Radix(nums){
  let maxDigitCount = mostDigitCount(nums)
  for(let k=0; k< maxDigitCount; k++) {
    let digitbucket = Array.from({length:10} , () => [])
    for(let i=0; i< nums.length; i++) {
      let digit = getDigit(nums[i], k)
      digitbucket[digit].push(nums[i])
    }
    nums = [].concat(...digitbucket)
  }
  return nums
}

console.log(Radix([23,123, 23333,444444,55555555]))

Example 2: radix sort

//Code by Soumyadeep
//insta id: @soumyadepp

#include <bits/stdc++.h>
#define ll long long

using namespace std;

int maxElement(vector<int> arr)
{
    int m = arr[0];
    for (int i = 0; i < arr.size(); i++)
    {
        if (arr[i] > m)
            m = arr[i];
    }
    return m;
}

int digitCnt(int x)
{
    int z = x;
    int c = 1;
    while (z)
    {
        z /= 10;
        c++;
    }
    return c;
}
void radixSort(vector<int> &arr)
{
    int x = maxElement(arr);               //O(N)
    int countDigits = digitCnt(x);         //O(numberofdigitsinx)
    for (int i = 1; i <= countDigits; i++) //runs number of digits in maximum element in the array
    {
        vector<int> holder[10];
        for (int j = 0; j < arr.size(); j++) //O(N)
        {
            int m = i;
            int k;
            int p = arr[j];
            while (m) //O(logN)
            {
                k = p % 10;
                p /= 10;
                m--;
            }
            holder[k].push_back(arr[j]);
        }
        arr.clear();
        for (int c = 0; c < 10; c++)
        {
            arr.insert(arr.end(), holder[c].begin(), holder[c].end());
        }
    }
    //approx O(ND)
}
int main()
{
    int t;
    cin >> t;
    while (t--)
    {
        vector<int> arr;
        int n, x;
        cin >> n;
        for (int i = 0; i < n; i++)
        {
            cin >> x;
            arr.push_back(x);
        }
        radixSort(arr);
        cout << "The sorted array is " << endl;

        for (int i = 0; i < arr.size(); i++)
            cout << arr[i] << " ";
        cout << endl;
    }
    return 0;
}