overloading << with template class

[dorA26]

I had to create a list class and add a "<<" function.
this is the code I wrote:

template <class T> 
class Node
{
private:
	T val;
	Node <T> * next;

public:
	Node <T> (const T & x)
	{
		val = x;
		next = 0;
	}

	void setVal (const T& x) { val = x; }

	T getVal () { return val; }

	void setNext (Node <T> * x) { next = x; }

	Node <T> * getNext () { return next;}

};

template <class T>
class List
{
private:
	Node <T> * n;
	int size;

public:

	List<T> () { n = 0, size = 0; }

	 Node <T> *  add (Node <T> * pos,const  T & x)
	{
		Node <T> * temp = new Node <T> (x);

		if (size == 0)
		{
			n = temp;
			pos = n;
		}

		else
		{
			if (pos == 0 && size!= 0)
			{
				temp -> setNext(n);
				n = temp;
				pos = n;
			}

			else
			{
				Node <T> * p = n;
				while ( p != pos)
					p = p -> getNext();
				p -> setNext(temp);
				pos = p -> getNext();
			}
		}
		++size;
		return pos;
	}

	 Node <T> * remove (Node <T> * pos)
	 {
		 if (pos == n && size == 1)
		 {
			 --size;
			 n = 0;
			 return 0;
		 }

		 int counter = 1;
		 Node <T> * p = n;

		 while ( (p -> getNext()) != pos)
		 {
			 ++counter;
			 p = p -> getNext();
		 }

		 if (pos -> getNext() == 0)
			 p -> setNext(0);

		 p -> setNext ( pos ->getNext() );

		 --size;
		 return p -> getNext();
	 }

	 Node <T> * search (Node <T> * pos)
	 {
		 Node <T> * p = n;
		 while ( p != pos )
		 {
			 p = p -> getNext();
		 }

		 return p;
	 }

	 int getSize () { return size; }

	template <typename T1>
	friend ostream& operator<< (std :: ostream& , const List<T1>& );

};

template <typename T>
ostream& operator << (std:: ostream& os, const List<T> & lst)  
{
	os << "[" << lst.n -> getVal();

   Node <T> * p = lst.n -> getNext ();

   for (int i = 1; i < lst.size; ++i)
   {
	   os << " , " << p ->getVal();
	   p = p -> getNext();
   }

   os << "]";

   return os;
}


int main ()

{
	Node <char> * a;

	Node <char> * b;

	List <char> * lst = new List <char> ();

	a = lst -> add(0,'a');
	a = lst -> add (a, 'b');
	b = a;
	a = lst -> add (a, 'D');
	a = lst -> remove (b);

	cout << a -> getVal() << endl;

	cout << lst;

	return 0;
}

the last line (cout << lst) prints a random number (I think it's the os address..?). can anyone tell me what's wrong with it?

[Catfish2]

lst is a pointer. So you're printing the contents of a pointer, which is naturally an address.

You are overusing pointers in my opinion. You also have a memory leak because you must pair each new with a delete.

So you must dereference the pointer by using the asterisk operator, and also delete lst; in the end.

int main ()
{
	Node<char> *a;
	Node<char> *b;
	List<char> *lst = new List<char>();

	a = lst->add(0,'a');
	a = lst->add(a, 'b');
	b = a;
	a = lst->add(a, 'D');
	a = lst->remove(b);
	cout << a->getVal() << endl;
	cout << *lst;
	delete lst;
	return 0;
}

Also I would suggest you compact your code a little.

[dorA26]

thanks!