关于数组的面试题

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

namespace Test
{
    class Program
    {
       
        public static void DobuNums(ref int[] nums)
        {
            for (int i = 0; i < nums.Length; i++)
            {
                nums[i] = nums[i] * 2;
                
            }
            nums = new int[] { 7, 8, 9 }; //若注释这一行结果又是什么

        }

        int[] nums = new int[] {2,3,4};

        public static void Main(string[] args)
        {

            int[] nums = new int[] { 1, 2, 3 };
            int[] copyNums = nums;
            object cloneNums = nums.Clone();
            string numsStr = null;

            for (int i = 0; i < nums.Length; i++)
            {
                numsStr += nums[i];
            }
            numsStr += "\n";
            DobuNums(ref nums);


            for (int i = 0; i < nums.Length; i++)
            {
                numsStr += nums[i];
            }
            numsStr += "\n";

            for (int i = 0; i < copyNums.Length; i++)
            {
                numsStr += copyNums[i];
            }

            numsStr += "\n";
            if (ReferenceEquals(nums, copyNums))
            {
                Console.WriteLine(numsStr);
                Console.WriteLine("nums ReferenceEquals copyNums");
            }
            else
            {
                Console.WriteLine(numsStr);
                Console.WriteLine("nums is not ReferenceEquals copyNums");
            }

            Console.ReadKey();
        }
    }
}

这是笔试的一道题，供大家参考。