using System;

​

public class Program

{

    public static void Main()

    {

        int[, ] matrix = new int[, ]

        {

            {1, 2, 3}, 

            {4, 5, 6}, 

            {7, 8, 9}

        };

        Console.WriteLine(matrix[0, 2]); // "3"

        Console.WriteLine(matrix[0, ^1]); // 編譯失敗！

    }

}