如何修复代码以使C#中的斐波那契搜索算法正常工作

using System;

class Program
{
    static int FibonacciSearch(int[] arr, int target)
    {
        int n = arr.Length;
        int fib2 = 0; // 第二个斐波那契数
        int fib1 = 1; // 第一个斐波那契数
        int fib = fib1 + fib2; // 当前斐波那契数

        while (fib < n)
        {
            fib2 = fib1;
            fib1 = fib;
            fib = fib1 + fib2;
        }

        int offset = -1; // 偏移量

        while (fib > 1)
        {
            int i = Math.Min(offset + fib2, n - 1);

            if (arr[i] < target)
            {
                fib = fib1;
                fib1 = fib2;
                fib2 = fib - fib1;
                offset = i;
            }
            else if (arr[i] > target)
            {
                fib = fib2;
                fib1 = fib1 - fib2;
                fib2 = fib - fib1;
            }
            else
            {
                return i; // 目标元素的索引
            }
        }

        if (fib1 == 1 && arr[offset + 1] == target)
        {
            return offset + 1; // 目标元素的索引
        }

        return -1; // 未找到目标元素
    }

    static void Main()
    {
        int[] arr = { 1, 3, 5, 7, 9, 11, 13, 15 };
        int target = 9;

        int index = FibonacciSearch(arr, target);

        if (index != -1)
        {
            Console.WriteLine("目标元素 {0} 的索引为 {1}", target, index);
        }
        else
        {
            Console.WriteLine("未找到目标元素 {0}", target);
        }
    }
}