head.h

使用中序遍历

template<class T>class BTree;//Note
template<class T>
class BTNode
{
	public:
		BTNode(){lchild = rchild = 0;}
		BTNode(const T & x){ element = x; lchild = rchild = 0;}
		BTNode(const T& x,BTNode<T> *l,BTNode<T> *r)
		{
			element = x;
			lchild = l;
			rchild = r;
		} 
	private:
		T element;
		BTNode<T> *lchild,*rchild;
		friend class BTree<T>;
		friend void Visit(BTNode<T> *);	
		friend void Change(BTNode<T> *);
};

template<class T>
void Visit(BTNode<T> * p )
{
	cout<<p->element<<" ";
}

template <class T>
void Change(BTNode<T>* p)
{ 
	cout<<"here in Change"<<endl;
   
}