Arithmetic:fun1(do while)

using System;

namespace ConsoleApplication1
{
    class Program
    {
        /// <summary>
        /// ylb: do while
        /// </summary>
        /// <param name="args"></param>
        static void Main(string[] args)
        {
            Console.Write(fun(2.5));
        }
        /// <summary>
        /// fun
        /// </summary>
        /// <param name="x"></param>
        /// <returns></returns>
        static double fun(double x)
        {
            double f, t;
            int n;
            f=1.0+x;
            t=x;
            n=1;   
            do
            {
                n++;
                t *= x / n; //这儿构思很其巧妙
                f += t;

            } while (Math.Abs(t) >= Math.Pow(10,-6));

            return f;
        }
    }
}