Thread: I wrote a piece of code, can't find where is the bug....

Dear All:

Here is the code I wrote.

Code:

#include <iostream>
using namespace std;

template <typename T>
class Stack;

template <typename T>
class Node{
private:
	Node * next;
	T* data;
public:
	friend class Stack<T>;
	Node():next(0),data(0){}
	Node( Node * head,  T * value):next(head),data(value){}
	Node * GetNext(){ return next; }
	void SetNext(const Node* newnext) {next = newnext;}
	T* GetData() { return data; }
	void SetData(const T* newdata) { data = newdata;}
	virtual ~Node(){}
};

template <typename T>
class Stack{
public:
	Stack():head(0){}
	void Push( T* data);
	T * Pop();
	T * Top();
	virtual ~Stack();
private:
	Node<T> * head;
};

template <typename T>
void Stack<T>::Push( T* data){
	head = new Node<T>(head,data);
}

template <typename T>
T* Stack<T>::Pop(){
	if (!head) return NULL;
	Node<T> * oldhead = head;
	T * result = head->GetData();
	head = head->GetNext();
	delete(oldhead);
	return result;
}

template <typename T>
T* Stack<T>::Top(){
	if (!head) return NULL;
	return (head->GetData());
}

template <typename T>
Stack<T>::~Stack(){
	while(head){ 
		Node<T>* oldhead = head;
		head = head->GetNext();
		delete(oldhead);
	}
}



int main(){
	Stack<int>* test = new Stack<int>;
	int x=1,y=2,z=3;
	test->Push(&x);
	test->Push(&y);
	test->Push(&z);
	cout<<*(test->Top())<<endl;
	test->Pop();
	cout<<*(test->Top())<<endl;
	delete(test);

	return 0;
}

This code implements a Stack.
I tried to declare: (with const)

Code:

Node( const Node * head,  const T * value):next(head),data(value){}

But it fails to complie... I am so confused....

BTW, I would polish this Stack as safe as possible, any suggestions to improve the robustness?