How do i define this function?

I'm sure it's the syntax, but i just keep fidlin' wit it and it still won't work. it's an unresolved symbol error

edit: it's all in the same file by the way

Code:

template<class _T>
class BTree
{
	//Forward Declaration
	public:
	class iterator;
	class in_iter;

	//Typedefs
	typedef _T * _Tpt;           // Template pointer type
	typedef BTree<_T> _Bt;	     // BTree type	
	typedef BTree<_T> * _Bpt;    // Btree pointer type
	typedef iterator _ItB;       // Iterator type base

	
	public:
	//Base class for all iterator types
	class iterator
	{
		public:

		_ItB operator=(const _Bpt);

		protected:
		_Bpt current;
	};


};


template<typename _T> 
BTree<_T>::_ItB   /* <-- return type | definition --> */
BTree<_T>::iterator::operator=(const _Bpt srcTree)
{
	current = &srcTree;
	return this;
}

Edit: this may help if the error is not as obvious as i hope for it to be


Linking...
main.obj : error LNK2001: unresolved external symbol "public: class BTree<int>::iterator __thiscall BTree<int>::iterator:perator=(class BTree<int> * const)" (??4iterator@?$BTree@H@@QAE?AV01@QAV1@@Z)
Debug/btree02.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

well, i got the operator= to work in dev-c++. now i can't get
_T operator*(void) to work!

it's basically the same thing!