template<class Type> class ThreadNode{  friend class ThreadTree;  friend class ThreadInorderIterator;  private:    int leftThread,rightThread;    ThreadNode<Type> * leftChild,* rightChild;    Type data;  public:    ThreadNode(const Type item):data(item),leftChild(NULL),rightChild(NULL),	  leftThread(0),rightThread(0){}	  };template<class Type>class ThreadTree{  friend class ThreadInorderIterator;  public:    void InThread(ThreadNode<Type> *,ThreadNode<Type> *);    void CreateInThread();    void InsertRight(ThreadNode<Type> *,ThreadNode<Type> *);  private:    ThreadNode<Type> * root;    };template<class Type> class ThreadInorderIterator{  public:    ThreadInorderIterator(ThreadTree<Type> & Tree): T(Tree){current=T.root;}    ThreadNode<Type> * First();    ThreadNode<Type> * Last();    ThreadNode<Type> * Next();    ThreadNode<Type> * Prior();  private:    ThreadTree<Type> & T;    ThreeNode<Type> * current;    }  template<class Type> ThreadNode<Type> * ThreadInorderIterator<Type>::First(){    while(current->leftThread==0)current=current->leftChild;    return current;    }  template<class Type> ThreadNode<Type> * ThreadInorderIterator<Type>::Next(){    ThreadNode<Type> * p=current->rightChild;    if(current->rightThread==0)      while(p->leftThread==0)p=p->leftChild;    current=p;    if(current==T.root) return NULL;    else return current;    }  template<class Type> void ThreadInorderIterator<Type>::Inorder(){    ThreadNode<Type> * p;    for(p=First();p!=NULL;p=Next())cout<<p->data<<endl;    }  template<class Type> void ThreadTree<Type>::InThread(ThreadNode<Type> * current,ThreadNode<Type> * pre){    if(current!=NULL){      InThread(current->leftChild,pre);      if(current->leftChild==NULL){	current->leftChild=pre;	current->leftThread=1;	}      if(pre->rightChild==NULL){	pre->rightChild=current;	pre->rightThread=1;	}      pre=current;      InThread(current->rightChild,pre);      }    }  template<class Type> void ThreadTree<Type>::CreateInThread(){    ThreadNode<Type> * pre;    root=new ThreadNode<Type>;    root->leftThread=1;    root->rightThread=0;    if(this==NULL){      root->leftChild=root;      root->rightChild=root;      }      else{	current=root->leftChild=this;	root->leftThread=0;	pre=root;	InThread(current,pre);	pre->rightChild=root;	pre->rightThread=1;	}      }  template <class Type> void ThreadTree<Type>::InsertRight ( ThreadNode<Type> *s,	    ThreadNode<Type> *r ) {    r->rightChild = s->rightChild;    r->rightThread = s->rightThread;    r->leftChild = s;  r->leftThread = 1;    s->rightChild = r;  s->rightThread = 0;    if ( r->rightThread == 0 ) {      current = r->rightChild;      ThreadNode<Type> *temp = First ( );      temp->leftChild = r;    }  }