Rotate array to the right of a given pivot, 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)
        {
            //Your code goes here
            Console.WriteLine("Hello, world!");
            int []arr = { 1, 2, 3, 4, 5, 6 }; 
            RotateArrayRight rot = new RotateArrayRight();
            
            Console.Write(" The array before rotate : " ) ;
            rot.Display(arr);
            
            rot.Rotate(arr, 7);
            Console.WriteLine();
            Console.Write(" The array after rotate : " ) ;
            rot.Display(arr);
        }
    }
    
    public class RotateArrayRight
    {
        //Rotate array to the right of a given pivot
        public int[] Rotate(int[] arr, int pivot)
        {
            if (pivot < 0 || arr == null)
                throw new Exception("Invalid argument");
 
            // if pivot is grater then the array size, take remainder
            pivot = pivot % arr.Length;
 
            //Rotate first half
            arr = RotateSub(arr, 0, pivot - 1);
 
            //Rotate second half
            arr = RotateSub(arr, pivot, arr.Length - 1);
 
            //Rotate all
            arr = RotateSub(arr, 0, arr.Length - 1);
 
            return arr;
        }
 
        private int[] RotateSub(int[] subArray, int start, int end)
        {
            while (start < end)
            {
                int temp = subArray[start];
                subArray[start] = subArray[end];
                subArray[end] = temp;
                start++;
                end--;
            }
            return subArray;
        }
        
        public void Display(int []arr) { 
            int n = arr.Length; 
            for (int i = 0; i < n; ++i) 
                Console.Write(arr[i] + " "); 
            Console.WriteLine(); 
         }
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0,3 sec, absolute running time: 0,2 sec, cpu time: 0,19 sec, average memory usage: 16 Mb, average nr of threads: 3, absolute service time: 0,52 sec