switch语句

Question

Console.Write("请输入您的分数：");
            int fenShu = int.Parse(Console.ReadLine());
            switch (fenShu)
            {
                case 90<fenShu<100:
                    Console.WriteLine("A");
                    break;
                case 80<fenShu<90:
                    Console.WriteLine("B");
                    break;
                case 70<fenShu<80:
                    Console.WriteLine("C");
                    break;
                case 60<fenShu<70:
                    Console.WriteLine("E");
                    break;
                default:
                    Console.WriteLine("不合格！");
            }编译不过：运算符“<”无法应用于“bool”和“int”类型的操作数.
我看过很多例子，case后跟的条件都是常数，所以我就自己做了这个例子。case后面不能跟一个范围吗？高手帮我改一下上面的例子，应该怎么写。谢谢！

Answer 1

不行 case后面只能放常量你可以这样
int fenShu = int.Parse(Console.ReadLine());
if(90<fenShu<100) str = "90-100";
if(80<fenShu<90) str = "80-90";
//....
            switch (str)
            {
                case "90-100":
                    Console.WriteLine("A");
                    break;
                case "80-90":
                    Console.WriteLine("B");
                    break;
                .......
            }

Answer 2

if..else if..else..
就好了。

Answer 3

fenshu/10取整，当 fenshu/10==8时，表明80<=fenshu<90