lstack.h

对堆栈进行了底层实现

//LStack.h
template <class Elem>
class Link
{
public:
	Link* next;
	Elem element;
	Link(Link<Elem>* lp = 0)
	{
		next = lp;
	}
	Link(const Elem& e,Link<Elem>* lp = 0)
	{
		element = e;
		next = lp;
	}
};

template <class Elem>
class LStack
{
private:
	Link<Elem>* head;
	int size;
public:
	LStack(int sz = 100)
	{
		size = 0;
		head = 0;
	}

	~LStack()
	{
	}
		
	void Clear()
	{
		while(head != 0)
			Pop();
	}

	bool Push(const Elem& value)
	{
		Link<Elem>* temp = new Link<Elem>;
		temp->element = value;

		temp->next = head;
		head = temp;
		size++;
		return true;
	}

	Elem Top()const
	{
		if(head == 0)
		{
			cerr << "Error:there is nothing in stack!" << endl;
			return (Elem)0;
		}
		return head->element;
	}

	bool Top(Elem& value)
	{
		if(head == 0)
			return false;
		value = head->element;
		return true;
	}

	bool Pop()
	{
		if(head == 0)
		{
			cerr << "Error:nothing can pop!" << endl;
			return false;
		}
		Link<Elem>* temp;
		temp = head->next;
		delete head;
		head = temp;
		size--;
		return true;
	}

	int Size()const
	{
		return size;
	}

	bool Empty()const
	{
		if(head == 0)
			return true;
		return false;
	}
};