---

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

namespace сава
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //zadanie 1
            /*
            double sum = 0;
            double[] temperatures = new double[] {22.5, 25.0, 21.8, 24.2, 23.5};
            for(int i = 0; i < temperatures.Length; i++)
            {
                sum = sum + temperatures[i];
            }
            Console.WriteLine(sum / temperatures.Length);
            */

            //zadanie 2
            /*
            string[] words = new string[] {"Hello", "World", "C#", "Array", "Example", "erfhi"};
            for (int i = 1; i <= 3; i++)
            {
                Console.WriteLine(words[^i]);
            }
            */

            //zadanie 3
            /*
           int[] numbers1 = {1, 2, 3, 4, 5};
           int[] numbers2 = {};
           Console.WriteLine(GetLastElement(numbers1));
           Console.WriteLine(GetLastElement(numbers2));
            */

            //zadanie 4
            string[] names = new string[] 

        }
         public static int? GetLastElement(int[] arr)
            {
                if (arr == null || arr.Length == 0)
                {
                    return null;
                }

                return arr[arr.Length - 1];
            }
    }
}