入门练习。

namespace 你的成绩及格吗？

{     class Program     {         static void Main(string[] args)         {                      double a;             while (true )

{                 Console.WriteLine("请输入你的姓名");                 Console.ReadLine();                 Console.WriteLine("请输入你的分数");                 a = Convert.ToDouble (Console.ReadLine());                 if (a >= 60 && a <= 100)                 {                     Console.WriteLine("恭喜你！及格了");                     if (a > 80)                     {                     Console.WriteLine("你学的不错，值得表扬！");                     }                 }                 else if (a >= 50 && a < 60)                 {                     Console.WriteLine("就差一点点，再加把油！");                     if (a < 50 && a >= 0)                     {                         Console.WriteLine("继续努力，不要偷懒！");                     }                 }                 else                 {                     Console.WriteLine("请输入正确的分数！");                 }                 Console.ReadLine();