集合随机数，最大值平均值

 

 var r = new Random();
            List<int> list = new List<int>();
            for (int i = 0; i < 100; i++)
            {
                int num = r.Next(1, 101);
                list.Add(num);
            }
            Console.WriteLine(list.Max());// 最大值

             list.Sort();
             list.Reverse();
            foreach (var item in list)
            {
                Console.Write(item + " ");
            }
            Console.WriteLine(); // 从大到小
            
            Console.WriteLine(list.Average());//平均