using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Factorial {     class Program     {         static void Main(string[] args)         {             Function obj = new Function();             Console.WriteLine("Would you like to know which number of Factorial：");             int number = Convert.ToInt32(Console.ReadLine());             Console.WriteLine();             Console.Write("The Fibonacci of {0} is：{1}", number, obj.Factorial(number));             Console.WriteLine();             Console.Write("The FactorialRecursion of {0} is：{1}", number, obj.FactorialRecursion(number));             Console.ReadKey();         }     } }

 using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Factorial {     class Function     {         /// <summary>         /// Factorial定义为：         ///      ┌ 1        n=0               ///   N!=│         ///      └ n(n-1)!  n>0         /// </summary>         /// <param name="number"></param>         /// <returns></returns>         public int Factorial(int number)         {             if (number != 0)             {                 return number * Factorial(number - 1);             }             else if (number == 0)             {                 return 1;             }             return number;         }         public int FactorialRecursion(int number)         {             int F = 1;             for (int i = 1; i <= number; i++)             {                 F *= i;             }             return F;         }     } }