using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var stringsEnumerator = DoStrings().GetEnumerator();

        var intsEnumerator = DoInts().GetEnumerator();

​

        while (stringsEnumerator.MoveNext()) {

            intsEnumerator.MoveNext();

            Console.WriteLine("Int: " + intsEnumerator.Current);

            Console.WriteLine("String: " + stringsEnumerator.Current);

        }

    }

    static IEnumerable<string> DoStrings() 

    {

        for(var i = 0; i < 1000; i++) {

            yield return "A" + i;

        }

    }

​

    static IEnumerable<int> DoInts()

    {

        for (var i = 0; i < 1000; i++)

        {

            yield return i;

        }

    }

}