例题：计算运费。c#语言基础，比较简单。看代码输入格式和方法。同样方法可以做一个 出租车打车的程序

            while (true)    

        {               

             Console.WriteLine("请输入行李重量");              

             double k = Convert.ToDouble(Console .ReadLine ());

                if (k >= 0 && k < 50)               

          {                    

            double m;           

             m = k * 0.25;        

             Console.WriteLine("您的运费为"+m+"元");

                }            

            else if (k >= 50)              

              {             

              double m;                

              m = k * 0.25 + (k - 50) * 0.4;          

               Console.WriteLine("您的运费为" + m + "元");                    

                }              

             else               

              {

             Console.WriteLine("请输入正确的重量");

              }