四处报错都是 "max"does not exist in the current context,

           string[] a = new string[] { "一", "二", "三", "四", "五", "六" };
            int[] b = new int[] { 80, 90, 98, 89, 86, 68 };
            int k = 0;
            max= b[0];
            for(int i=0;i<b.Length;i++)
            {
                if(b[i]>max)
                {
                    max= b[i];
                    k = i;
                }
            }
            Console.Write("得分最高人的名字是" + a[k] + ",  分数是" + max);