CalculateEquation

using System;

//Write a program that, for a given two integer numbers n and x, calculates the sum S = 1 + 1!/x + 2!/x2 + … + n!/xn. Use only one loop.
//Print the result with 5 digits after the decimal point.

    class CalculateEquation
    {
        static void Main()
        {
            Console.Write("N = ");
            int n = int.Parse(Console.ReadLine());
            Console.Write("X = ");
            int x = int.Parse(Console.ReadLine());

            int fakN = 1;
            int powX = 1;
            double sum = 1;
            for (int i = 1; i <= n; i++)
            {
                powX *= x;
                fakN *= i;
                sum += ((double)fakN / powX);
            }
            Console.WriteLine("sum = {0:F5}",sum);
        }
    }