06.LoopsHomework/05.Calculate

//Problem 5. Calculate 1 + 1!/X + 2!/X2 + … + N!/XN
//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.

using System;
class Calculate
{
    static ulong FactorialCalc(uint number)
    {
        ulong sum = 1;
        for (uint i = 1; i <= number; i++)
        {
            sum = sum * i;
        }
        return sum;
    }

    static void Main()
    {
        Console.Write("Please, enter X:");
        double x = int.Parse(Console.ReadLine());
        Console.Write("Please, enter N:");
        double n = int.Parse(Console.ReadLine());
        double theSum = 1;
        for (uint i = 1; i <= n; i++)
        {
            theSum = theSum + (FactorialCalc(i) / Math.Pow(x, i));
        }
        Console.WriteLine("S=1+1!/X+2!/X2+...+N!/XN = {0}",theSum);
    }
}