quick sort

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace quick_sort
{
    class Program
    {
        static void Main(string[] args)
        {
            //Quick Sort with Recursion
            int[] arr = { 8, 6, 1, 4, 9, 2, 3 };
            int start = 0;
            int pivot = arr.Length - 1;
            quick_sort(arr, start, pivot);

            foreach(var item in arr)
            {
                Console.WriteLine(item);
            }
        }
        static int partition(int []arr, int start,int pivot)
        {
            int i = start - 1;
            for(int j= start; j<= pivot-1; j++)
            {
                if(arr[j] <= arr[pivot - 1])
                {
                    i = i + 1;
                    int temp = arr[i];
                    arr[i] = arr[j];
                    arr[j] = temp;
                }
            }
            int tmp = arr[pivot];
            arr[pivot] = arr[i + 1];
            arr[i + 1] = tmp;
            return i + 1;

        }
        static void quick_sort(int []arr,int start,int pivot)
        {
            if(start <= pivot)
            {
                int q = partition(arr, start, pivot);
                quick_sort(arr, start, q - 1);
                quick_sort(arr, q + 1, pivot);
            }
        }
    }
}