Factorial.cs

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

namespace factorial
{
    class factor
    {
        public int factorial(int value)
        {
            int fac = 1;
            if (value > 1)
            {
                fac = value * factorial(value - 1);
            }
            return fac;
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            factor f = new factor();
            Console.WriteLine("Enter value to get factorial");
            int value = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("Factorial : {0}", f.factorial(value));
            Console.ReadLine();
        }
    }

}