How to reverse a string with an extension method?

Question

C++ / C#

It is necessary to solve the problem of reversing an array of integers using the extension method, actually read about these methods and wrote a method that does not give errors and warnings, but also does not work, tell me, could there be a problem?

Program.cs

using System;

namespace Lab10
{
    internal static class Program
    {
        
        public static void Main(string[] args)
        {
            int[] array = new[] {1, 4, 5, 1, 3, 235, 634, 234, 12, 4, 3, 77, 141};
            array.PrintArray();

            array.ReverseArray();

            Console.WriteLine();
            foreach (var elem in array)
            {
                Console.Write($"{elem} _ ");
            }
        }
    }
}

Extension.cs

...
public static int[] ReverseArray(this int[] arr)
        {
            List<int> buffer = arr.ToList();
            buffer.Reverse();
            arr = buffer.ToArray();
            return arr;
        }
...

Answer 1

for (int i = 0; i < arr.Length / 2; i++)
{
   int tmp = arr[i];
   arr[i] = arr[arr.Length - i - 1];
   arr[arr.Length - i - 1] = tmp;
}

Answer 2

I take it you have a study assignment?
If not, you can:
1. Convert array to List using .ToList
2. Run .Reverse command on List 3. Convert
List back to array with .ToArray command
Three lines of code.