using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var q = new StringQueue("abcdefghij");

​

        Console.WriteLine(q.Next(3));

        Console.WriteLine(q.Next(3));

        Console.WriteLine(q.Next(3));

        Console.WriteLine(q.Next(3));

        Console.WriteLine(q.Next(3));

        Console.WriteLine("---------------");

        new StringQueue("abcdefghij")

            .Next(3, out string first)

            .Next(3, out string second)

            .Next(3, out string third);

        Console.WriteLine(first);

        Console.WriteLine(second);

        Console.WriteLine(third);

        Console.WriteLine("---------------");

        new StringQueue("abc123ghij")

        .Next(3, out string first2)

        .Next(3, out int second2, s => Convert.ToInt32(s))

        .Next(3, out string third2);

         Console.WriteLine(first2);

         Console.WriteLine(second2);

         Console.WriteLine(third2);

    }

}

​

public class StringQueue

{

    private readonly string original;

    private int index;

​

    public StringQueue(string data)

    {

        this.original = data;

        this.index = 0;

    }

    public string Next(int count)

    {

        var chars = original.Skip(this.index).Take(count).ToArray();

        this.index += count;

        return new string(chars);

    }

    public StringQueue Next(int count, out string result)

    {

        result = Next(count);

        return this;

    }

    public StringQueue Next<T>(int count, out T result, Func<string, T> convert)

    {

        result = convert(Next(count));

        return this;

    }

}