QuickSort

using System;
using System.Linq;
namespace QuickSort
{
    public class Program
    {
        /*  This function takes last element as pivot,
            places the pivot element at its correct
            position in sorted array, and places all
            smaller (smaller than pivot) to left of
            pivot and all greater elements to right
            of pivot */
        int partition(int[] arr, int low, int high)
        {
            int pivot = arr[high];
            int i = (low - 1); // index of smaller element
            for (int j = low; j <= high - 1; j++)
            {
                // If current element is smaller than or
                // equal to pivot
                if (arr[j] <= pivot)
                {
                    i++;

                    // swap arr[i] and arr[j]
                    int intTemp = arr[i];
                    arr[i] = arr[j];
                    arr[j] = intTemp;
                }
            }

            // swap arr[i+1] and arr[high] (or pivot)
            int temp = arr[i + 1];
            arr[i + 1] = arr[high];
            arr[high] = temp;

            return i + 1;
        }

        /*  The main function that implements QuickSort()
            arr[] --> Array to be sorted,
            low --> Starting index,
            high --> Ending index */
        void sort(int[] arr, int low, int high)
        {
            if (low < high)
            {
                /*  pi is partitioning index, arr[pi] is 
                    now at right place */
                int pi = partition(arr, low, high);

                // Recursively sort elements before
                // partition and after partition
                sort(arr, low, pi - 1);
                sort(arr, pi + 1, high);
            }
        }
        /* A utility function to print array of size n */
        static void printArray(int[] arr)
        {
            int n = arr.Count();
            for (int i = 0; i < n; ++i)
                Console.WriteLine(arr[i] + " ");
            Console.Read();
        }
        public static void Main(string[] args)
        {
            int[] arr = { 10, 7, 8, 9, 1, 5 };
            int n = arr.Count();

            Program ob = new Program();
            ob.sort(arr, 0, n - 1);

            Console.WriteLine("sorted array");
            printArray(arr);
        }
    }
}