//程序清单P5_2.cs:
using System;
namespace P5_2
{
    class WhileCycleSample
    {
         static void Main()
         {
               Console.WriteLine("请输入1~5之间的一个分数（按X键退出）：");
               char ch = Console.ReadKey().KeyChar;
               while (ch != 'x' && ch != 'x')
               {
                     switch (ch)
                     {
                           case '5':
                                Console.WriteLine("优秀");
                                break;
                           case '4':
                                Console.WriteLine("良好");
                                break;
                           case '3':
                                Console.WriteLine("及格");
                                break;
                           case '2':
                                Console.WriteLine("不及格");
                                break;
                           case '1':
                                Console.WriteLine("不及格");
                                break;
                            default:
                                Console.WriteLine("请输入1~5之间的整数");
                                break;
                       }
                Console.WriteLine("请输入分数（按X键退出）：");
                char ch = Console.ReadKey().KeyChar;
                }
          }
    }
}

语句错误CS0136：不能在此范围内声明名为“ch”的局部变量，因为这样会使“ch”具有不同的含义，而它已在“父级或当前”范围总表示其他内容了。

请问这个问题怎么解决？？
 char ch = Console.ReadKey().KeyChar;此语句是什么意思??

谢谢！！

OK！That's right! Thank you!