using System;

public class Program

{

    public class ArrayQueue<T> {

        private int _capacity = 10;

        private int _length = 0;

        private int _start = 0;

        private int _end = -1;

        private T[] _storage;

        public ArrayQueue() {

            _storage = new T[_capacity];

        }

        public void Enqueue(T elem) {

            if(_length == _capacity) {

                throw new Exception("queue overflow"); 

            }

            _storage[++_end % _capacity] = elem;

            _length++;

        }

        public T Dequeue() {

            if(_length == 0)

                throw new Exception();

            Console.WriteLine(_start);

            var elem = _storage[_start % _capacity];

            _storage[_start % _capacity] = default(T);

            _start++;

            _length--;

            return elem;

        }

        public int Length { get { return _length; } }

    }

    public static void Main()

    {

        var q = new ArrayQueue<int>();

        Console.WriteLine("len={0}", q.Length);

        q.Enqueue(2);

        Console.WriteLine("len={0}", q.Length);

        var elem = q.Dequeue();

        Console.WriteLine("len={0} elem={1}", q.Length, elem);

        q.Enqueue(3);

        Console.WriteLine("len={0}", q.Length);

        elem = q.Dequeue();

        Console.WriteLine("len={0} elem={1}", q.Length, elem);

        q.Enqueue(4);

        Console.WriteLine("len={0}", q.Length);

        elem = q.Dequeue();

        Console.WriteLine("len={0} elem={1}", q.Length, elem);

        for(int i = 1; i <= 10; i++) {

            q.Enqueue(i);

        }

        Console.WriteLine("len={0}", q.Length);

        var queueContent = new int[q.Length];

        for(int i = 0; i < 10; i++) {

            queueContent[i] = q.Dequeue();

        }

        Console.WriteLine("len={0} elems={1}", q.Length, string.Join(",", queueContent));

    }

}