rotate array - algorithm, move to right one position

rotateArray.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace RotateArray2
{
    class Program
    {
        static void Main(string[] args)
        {
            int k = Convert.ToInt16(Console.ReadLine()); 

            int[][] arr = new int[k][]; 

            for(int i=0; i<k; i++)
                arr[i] = new int[k]; 

            for(int i=0;i<k;i++)
            {
                string s = Console.ReadLine();
                string[] aA = s.Split(' ');
                if (aA.Length != k)
                    return;
                for (int j = 0; j < k; j++)
                    arr[i][j] = Convert.ToInt16(aA[j].Trim()); 
            }

            if (rotateArray(arr, k))
            {
                for(int i=0;i<k;i++)
                {
                    string s = "";
                    for (int j = 0; j < k; j++)
                        s += arr[i][j].ToString() + " ";
                    Console.WriteLine(s); 
                }
            }
            else
                Console.WriteLine("ERROR"); 
        }

        /*
         * Do it in place
         */
        public static bool rotateArray(int[][] arr, int k)
        {
            if (arr == null) return false;
            int n = arr.Length;  // row
            int m = arr[0].Length; // column

            if (n != m) return false;
            if(n!=k) return false; 

            int start = 0;
            int end = k-1; 

            while(start <= end && start <k/2)
            {
                // for left column 
                swap(arr, start, start, start, start+1, k); 
                for(int i=start+1; i<=end; i++)
                {
                    swap(arr, i, start, i -1, start, k); 
                }

                // for down row - swap 
                for (int i = start; i < end; i++)
                {
                    swap(arr, end, i, end, i+1, k);
                }
                // for right column
                for (int i = end; i > start; i--)
                {
                    swap(arr, i, end, i - 1, end,  k);
                }
                // for up row 
                for (int i = end; i >start+2; i--)
                {
                    swap(arr, start, i, start, i-1, k);
                }
                start++;
                end--; 
            }
            return true; 
        }

        private static void swap(int[][] arr, int x1, int y1, int x2, int y2, int maxRow)
        {
            if (!(x1 < maxRow && y1 < maxRow && x2 < maxRow && y2 < maxRow))
                return;

            if (!(x1 >= 0 && y1 >= 0 && x2 >= 0 && y2 >= 0))
                return; 

            int tmp = arr[x1][y1]; 
            arr[x1][y1] = arr[x2][y2];
            arr[x2][y2] = tmp; 
        }
    }
}