using System;

using System.Collections;

using System.Collections.Generic;

public class FixedStack<T>

{

private T[] items;

private int count;

const int n = 10;

public FixedStack()

{items = new T[n];}

public FixedStack(int length)

{items = new T[length];}

public bool IsEmpty

{get {return count ==0;}

}

public int Count

{get {return count;}

}

    public void Push(T item)

    {

    if(count == items.Length)

    throw new InvalidOperationException("");

    items[count++]=item; }

    public T Pop()

    {

    if(IsEmpty)

    throw new InvalidOperationException("");

    T item = items[--count]; }

    items[count]=default(T);

    return item;}

    public T Peek()

    {

        if (IsEmpty)

    throw new InvalidOperationException("");

    return items[count-1]; }

    }

    }

}