C#实现费波纳奇序列

1,1,2,3,5,8,13,21,34,55,89.....
求第30位结果：



        

static void Main()
        {

            Console.WriteLine(Fib(30));
        }
        static int Fib(int i)
        {
            if (i <= 0)
            {
                return 0;
            }
            else if (i > 0 && i <= 2)
            {
                return 1;
            }
            else
            {
                return Fib(i - 1) + Fib(i - 2);
            }
        }