Reverse Array (!Array.Reverse()), C#

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//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

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

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            int[] source = { 1, 2, 3, 4, 5 };
            
            int[] reversed = ReverseArray(source);
            
            foreach (int i in reversed)
                Console.Write(i.ToString() + " ");
            
        }
        
        public static int[] ReverseArray(int[] a)
        {
            int[] reversed = new int[a.Length];
            int index;
            int j; // reversed index
            
            for (index = a.Length - 1, j = 0; index >= 0; index--, j++)
            {
                reversed[j] = a[index];
            }
            
            return a = reversed.ToArray();
            
        }
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0,19 sec, absolute running time: 0,08 sec, cpu time: 0,09 sec, average memory usage: 12 Mb, average nr of threads: 3