#pragma once
template<class T> class SHStack
{
public:
	
	SHStack(long depth = -1);
	
	virtual ~SHStack();
	
	virtual bool Pop(T&t) = 0;
	
	virtual bool Push(T const&t) = 0;

	virtual void GoBack() = 0;
	
	virtual void GoAhead() = 0;
	
	virtual void Clear() = 0;

	virtual long GetDepth() = 0;
	
	virtual bool GetTopData(T&t) = 0;
	
	virtual T& operator[](long i) = 0;

	void SetMaxDepth(long depth);
	
	long GetMaxDepth();
	
	bool IsDepthLimited();
	
	bool IsEmpty();

	bool CanGoBack();
	
	bool CanGoAhead();

protected:
	
	long maxDepth;
	
	long oldDepth;
};

template<class T> 
SHStack<T>::SHStack(long depth)
{
	maxDepth = depth;
	oldDepth = 0;
}

template<class T> 
SHStack<T>::~SHStack()
{

}

template<class T> 
void SHStack<T>::SetMaxDepth(long depth)
{
	maxDepth = depth;
}

template<class T> 
long SHStack<T>::GetMaxDepth() 
{
	return maxDepth;
}

template<class T> 
bool SHStack<T>::IsDepthLimited() 
{
	return maxDepth >= 0;
}

template<class T> 
bool SHStack<T>::IsEmpty() 
{
	return GetDepth() == 0;
}

template<class T> 
bool SHStack<T>::CanGoBack() 
{
	return !IsEmpty();
}

template<class T> 
bool SHStack<T>::CanGoAhead() 
{
	return oldDepth > GetDepth();
}