集合练习 去掉最高最低分

namespace ConsoleApplication18
{
    class Program
    {
        static void Main(string[] args)
        {
            ArrayList al = new ArrayList();
            Console.Write("请输入评为人数：");
            int n = Convert.ToInt32(Console.ReadLine());
            for (int i = 0; i < n; i++)
            {
                Console.Write("第" + (i + 1) + "评为的评分为：");//；利用for循环把输入的数放入集合中
                al.Add(Convert.ToInt32(Console.ReadLine()));
            }
            al.Sort();//从小到大排序
            for (int k = 0; k < n; k++)
            {
                Console.WriteLine(al[k]);
            }
            Console.WriteLine("以上为成绩升序");
            Console.ReadLine();
            double sum = 0;
            for (int j = 0; j < n; j++)//计算总分
            {
                sum = sum + Convert.ToDouble(al[j]);
            }
            double avg = (sum - Convert.ToDouble(al[0]) - Convert.ToDouble(al[n])) / (n - 2);
            Console.WriteLine("总成绩为:"+sum);
            Console.WriteLine(n + "个人的平均分数为：" + avg);
            Console.ReadLine(); 

        }
    }
}