Shell Sort

#include <iostream>
using namespace std;

void shellSort(int *arr, int n)
{
     int gap = 1;
     while (gap < n / 3)
     {
          gap = 3 * gap + 1;
     }
     while (gap >= 1)
     {
          for (int i = gap; i < n; i++)
          {
               for (int j = i; j >= gap && arr[j] < arr[j - gap]; j -= gap)
               {
                    swap(arr[j - gap], arr[j]);
               }
               gap /= 3;
          }
     }
}

int main()
{
     int arr[] = {5, 4, 3, 2, 1, 0};
     int n = sizeof(arr) / sizeof(arr[0]);

     shellSort(arr, n);
     for (int i = 0; i < n; i++)
     {
          cout << arr[i] << " ";
     }
}