快排实现

using System;
namespace test1
{
    class Program
    {
        /*
        IComparable接口提供CompareTo方法
        ref 可以去掉
        */
        public static void Quicksort<T>(ref T [] a,int low,int high) where T:System.IComparable<T> 
        {
            if(low>=high)
            {
                return;
            }
            int i = low, j = high + 1;
            T key = a[low];
            while(true)
            {
                while (a[++i].CompareTo(key)<0 && i < high) ; //a.CompareTo(b)>0 即 a>b
                while (a[--j].CompareTo(key)>0) ;
                if (i >= j)
                    break;
                T tmp = a[i];
                a[i] = a[j];
                a[j] = tmp;
            }
            a[low] = a[j];
            a[j] = key;
            Quicksort(ref a, low, j - 1);
            Quicksort(ref a, j + 1, high);
        }
        static void Main(string[] args)
        {
            int[] a = { 23, 412, 42, 45, 67, 3, 6, 34, 56 };
            Quicksort(ref a, 0, a.Length - 1);
            foreach(int element in a)
            {
                Console.WriteLine(element);
            }
        }
    }
}