nFact!

using System;
using System.Collections.Generic;
//Write a program to calculate n! for each n in the range [1..100]. Hint: Implement first a method that multiplies a number represented as array of digits by given integer number.

class CalculateN
{
    private static List<int> FactN(int index)
    {
        int[] mulIndex = new int[] { 1 };
        List<int> currentNum = new List<int> { 1 };
        List<int> number = new List<int>();
        int remainder = 0;
        int multiple = 0;

        for (int mulCount = 0; mulCount <= index; mulCount++)
        {
            mulIndex[0] = mulCount + 1;
            number = new List<int>(currentNum);
            remainder = 0;
            currentNum.Clear();

            for (int numCount = 0; numCount < number.Count; numCount++)
            {
                multiple = number[numCount] * mulIndex[0] + remainder;

                if (multiple > 9)
                {
                    int devider = multiple % 10;
                    currentNum.Add(devider);
                    remainder = multiple / 10;

                    if (numCount == number.Count - 1 && remainder > 0)
                    {
                        if (remainder > 9)
                        {
                            while (true)
                            {
                                int devRemainder = remainder % 10;
                                currentNum.Add(devRemainder);
                                remainder /= 10;
                                if (remainder == 0)
                                {
                                    break;
                                }
                            }
                        }
                        else
                        {
                            currentNum.Add(remainder);
                        }
                    }
                }
                else
                {
                    currentNum.Add(multiple);
                    remainder = 0;
                }
            }
        }
        return currentNum;
    }

    static void Main()
    {
        int n = int.Parse(Console.ReadLine());
        int[] factorial = FactN(n - 1).ToArray();

        for (int i = factorial.Length - 1; i >= 0; i--)
        {
            Console.Write(factorial[i]);
        }
    }
}