C#用递归算法实现：一列数的规则如下: 1、1、2、3、5、8、13、21、34，求第30位数是多少

/// <summary>/// 一列数的规则如下: 1、1、2、3、5、8、13、21、34求第30位数是多少， 用递归算法实现。(C#语言)/// </summary>/// <param name="pos"></param>/// <returns></returns>public int GetNumberAtPos(int pos){  if(pos==0||pos==1)  {    return 1;  }  int res = GetNumberAtPos(pos - 1) + GetNumberAtPos(pos - 2);  return res;}

using System;using System.Collections;using System.Collections.Generic;using System.Text;namespace Test{  public class Class1  {    private ArrayList list = new ArrayList();    public Class1()    {    }    public Class1(int num)      : base()    {      int i;      for (i = 1; i <= num; i++)      {        list.Add(Calculation(i));      }    }    private int Calculation(int num)    {      if (num == 1 || num == 2)        return 1;      else        return Convert.ToInt32(list[num - 2]) + Convert.ToInt32(list[num - 3]);    }    public int Calculation()    {      return Convert.ToInt32(list[list.Count - 1]);    }  }  public class test  {    public static void Main()    {      int j;      int num;      for (j = 1; j < 100; j++)      {        Console.WriteLine("你要计算第多少位:");        string readstr;        readstr = Console.ReadLine();        if (!string.IsNullOrEmpty(readstr))        {          if (int.TryParse(readstr, out num))          {            if (num < 1)              continue;            else            {              Class1 c1 = new Class1(num);              Console.WriteLine(c1.Calculation());            }          }          else          {            continue;          }        }        else        {          break;        }      }    }  }}

public long getNumber(int pos){  long one = 1;  long two = 1;  if (pos == 0 || pos == 1)  {    return 1;  }  int i = 3;  long sum = 1;  while (i <= pos)  {    sum = one + two;    one = two;    two = sum;    i++;  }  return sum;}