using System;

using System.Text.Json;

​

class Program

{

    static void Main(string[] args)

    {

​

        Index i1 = 3;  // number 3 from beginning

        Index i2 = ^4; // number 4 from end

        int[] a = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };

        Console.WriteLine($"{a[i1]}, {a[i2]}");

​

        ReadJson("[1,2,3,4]");

        Console.WriteLine("Hello World!");

    }

​

    public static void ReadJson(string jsonString)

    {

        using var document = JsonDocument.Parse(jsonString);

​

        var root = document.RootElement;

        foreach(var item in root.EnumerateArray())

        {

            Console.WriteLine(item);

        }

    }

}