using System;

namespace TodoApplication
{
    public class LimitedSizeStack<T>
    {
        private T[] array;
        private int limit;
        private int headPointer;
        private int tailPointer;

        public LimitedSizeStack(int limit)
        {
            this.limit = limit;
            array = new T[limit];
            headPointer = 0;
            tailPointer = 0;
        }

        public void Push(T item)
        {
            if (headPointer - tailPointer >= limit) {
                tailPointer++;
            }
            array[headPointer++ % limit] = item;
        }

        public T Pop()
        {
            if (headPointer == tailPointer)
                return default(T);
            return array[--headPointer % limit];
        }

        public int Count
        {
            get
            {
                return headPointer - tailPointer;
            }
        }
    }
}