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

namespace _2._1._1
{
    class TableOfElements
    {
        private Object thisLock = new Object();
        int[] Arr;
        public int sum = 0;
        Random r = new Random();

        public TableOfElements(int length)
        {
            Arr = new int[length];
            for (int i = 0; i < length; i++)
            {
                Arr[i] = r.Next(-100, 1000);
            }
        }

        public void SumArr(int elementNumber)
        {
            lock(thisLock)
            {
                sum += Arr[elementNumber-1];
                Console.WriteLine(this.sum);
            }
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            int n = 4; //number of elements in Array and threads
            TableOfElements tabOfEl = new TableOfElements(n);

            Thread[] threads = new Thread[n];
            for (int j = 0; j < n; j++)
            {
                Thread thread = new Thread(() => tabOfEl.SumArr(j));
                threads[j] = thread;
            }
            for (int i = 0; i < n; i++)
            {
                threads[i].Start();
            }
            Thread.Sleep(1000);
            Console.WriteLine("Sum (multithreaded with lock): " + tabOfEl.sum);
            Console.ReadKey();
        }
    }
}