using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace FactorialFinder
{
    class Program
    {
        static void Main(string[] args)
        {
            FactorialFinder();
        }

        static void FactorialFinder()
        {
            Console.WriteLine("Please enter a positive integer");

            string input = Console.ReadLine();

            if (Int32.TryParse(input, out int n))
            {
                if (n > 0)
                {
                    int temp1;
                    int temp2 = 1;
                    int eq=0;

                    for (int i = 0; i <= n; i++)
                    {
                        temp1 = n - i;
                        if (n - i == 0)
                        {
                            temp1 = 1;
                        }
                        eq = temp1 * temp2;
                        temp2 = eq;
                    }
                    Console.WriteLine("You factorial equals: {0}", eq);
                    Console.ReadKey();
                }
                else
                {
                    Console.WriteLine("That's not a positive integer");
                    Console.ReadKey();
                }
            }
            else
            {
                Console.WriteLine("Thats not a number");
                Console.ReadKey();
            }
        }
    }
}