int[] arr = { 21, 22, 23, 24, 25 };
            int[] arr2 = new int[arr.Length];
            arr2 = arr;
            for (int i = 0; i < arr.Length; i++)
            {
                arr[i] += 1;

            }
            Console.WriteLine(string.Join(" ", arr2));

            Console.WriteLine(string.Join(" ", arr));