using System;

public class Program

{

    public static void Main()

    {

        int[,] matrix = new int[,] 

        {

            {1, 2, 3, 4},

            {5, 6, 7, 8},

            {9, 10, 11, 12},

            {13, 14, 15, 16}

        };

        Display(matrix);

        int[,] newMatrix1 = RotateCW90deg(matrix);

        int[,] newMatrix2 = RotateCW90deg(newMatrix1);

        int[,] newMatrix3 = RotateCW90deg(newMatrix2);

        int[,] newMatrix4 = RotateCW90deg(newMatrix3);

    }

    public static void Display(int[,] matrix)

    {

        for (int i = 0; i < matrix.GetLength(0); i++)

        {

            for (int j = 0; j < matrix.GetLength(1); j++)

            {

                Console.Write(matrix[i, j] + "  ");

            }

            Console.WriteLine("");

        }

        Console.WriteLine("");

    }

​

    public static int[,] RotateCW90deg(int[,] matrix)

    {

        // first row -> first col

        // second row -> second col

        // ...

        Console.WriteLine("Rotating 90deg CW...\n");

        int[,] newMatrix = new int[matrix.GetLength(0), matrix.GetLength(1)];

​

        for (int i = 0; i < matrix.GetLength(0); i++)

        {

            for (int j = 0; j < matrix.GetLength(1); j++)

            {

                Console.WriteLine("moving " + matrix[i, j].ToString() + " to [" + (matrix.GetLength(0) - 1 - j).ToString() + ", " + i.ToString() + "]");

                newMatrix[matrix.GetLength(0) - 1 - j, i] = matrix[i, j];

            }

        }

        Console.WriteLine("");

        Display(newMatrix);

        return newMatrix;

    }

}