using System;

using System.Threading;

​

​

var evenThread = new Thread(EvenNumbers);

var oddThread = new Thread(OddNumbers);

evenThread.Start();

oddThread.Start();

​

void EvenNumbers()

{

    for (int i = 0; i <= 20; i += 2)

    {

        Console.WriteLine(i);

    }

}

​

void OddNumbers()

{

    for (int i = 1; i <= 20; i += 2)

    {

        Console.WriteLine(i);

    }

}