冒泡排序法vs快速排序法(c#)

class Program
    {
        static DateTime t1, t2;
        static TimeSpan ts1,ts2;
        static int c1 = 0, c2 = 0;
        static void quick_sort(int[] a, int start, int end)
        {
            int key, i, j, dir = -1;
            if (end <= start)
            {
                return;
            }
            i = start;
            key = a[i];
            j = end + 1;
            while (i < j)
            {
                c1++;
                if (dir == -1)
                {
                    if (a[--j] < key)
                    {
                        a[i] = a[j];
                        dir = 1;
                    }
                }
                else
                {
                    if (a[++i] > key)
                    {
                        a[j] = a[i];
                        dir = -1;
                    }
                }
            }
            a[i] = key;
            quick_sort(a, start, i - 1);
            quick_sort(a, i + 1, end);
        }
        static void bubble_sort(int[] a, int start)
        {
            int t;
            if(start==a.Length-1)
            {
                return;
            }
            for (int i = a.Length - 1; i >= start +1; i--)
            {
                c2++;
                if (a[i - 1] > a[i])
                {
                    t = a[i - 1];
                    a[i - 1] = a[i];
                    a[i] = t;
                }
            }
            bubble_sort(a, start + 1);
        }

        static void Main(string[] args)
        {
            int[] a,b;
            int length =100;
            a = new int[length*3];
            //init array
            for(int index=0,i=1,j=length+1,k= length*2+1; i<=length;i++,j++,k++)
            {
                a[index++] = i;
                a[index++] = j;
                a[index++] = k;
            }
            a.Reverse();
            b = new int[a.Length];
            a.CopyTo(b, 0);
            
            //bubble_sort start
            t1 = DateTime.Now;
            bubble_sort(b, 0);
            t2 = DateTime.Now;
            ts2 = t2.Subtract(t1);

            //quick_sort start
            t1 = DateTime.Now;
            quick_sort(a, 0, a.Length - 1);
            t2 = DateTime.Now;
            ts1 = t2.Subtract(t1);

           
            //output array
            ////Console.WriteLine("Array a:");
            ////foreach (var item in a)
            ////{
            ////    Console.Write(item + " ");
            ////}
            ////Console.WriteLine();
            ////Console.ReadKey();
            ////Console.WriteLine("Array b:");
            ////foreach (var item in b)
            ////{
            ////    Console.Write(item + " ");
            ////}
            ////Console.WriteLine();
            ////Console.ReadKey();
            Console.WriteLine($"Quick_sort spends {ts1.Milliseconds} ms.count={c1}");
            Console.WriteLine($"Bubble_sort spends {ts2.Milliseconds} ms.count={c2}");
            Console.ReadKey();
        }
    }