【数据结构】迭代器实现二叉树的中序遍历

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迭代器

template<class T,class Ref,class Ptr>struct __TreeIterator{typedef BinTreeNode<T> Node;typedef __TreeIterator<T,Ref,Ptr> Self;__TreeIterator(){}__TreeIterator(Node* node):_node(node){}Ref operator*(){assert(_node);return _node->_date;}Self& operator++(){assert(_node);if(_node->RightTag==Link){Node* right=_node->rightchild;while (right&&right->LeftTag==Link){right=right->leftchild;}_node=right;}else{_node=_node->rightchild;}return *this;}Self& operator++(int){Self tmp(*this);++(*this);return tmp;}Self& operator--(){assert(_node);if(_node->LeftTag=Link){Node* left=_node->leftchild;while (left&&left->RightTag==Link){left=left->rightchild;}_node=left;}else{_node=_node->leftchild;}return *this;}bool operator!=(const Self s) const{return _node!=s._node;}Node* _node;

T表示类型，Ref表示引用，Ptr表示指针

二叉树的实现

需要实现begin和end

template <class T>class BinTree{typedef BinTreeNode<T> Node;public:typedef __TreeIterator<T,T&,T*> Iterator;typedef __TreeIterator<T,const T&,const T* > ConstIterator;Iterator Begin(){Node* cur=_root;while (cur&&cur->LeftTag==Link){cur=cur->leftchild;}return Iterator(cur);}ConstIterator Begin()const;Iterator End(){return Iterator(0);}ConstIterator End()const;BinTree():_root(NULL){}BinTree(T* a,size_t size,const T& invalid):_root(NULL){size_t index=0;_CreateTree( _root,a,size,index,invalid);}void InOrderThead(){Node* pre=NULL;_InOrderThead(_root,pre);}protected:void  _CreateTree(Node*& root,T a[],size_t size,size_t& index ,const T& invalid){assert(a);if(index< size&& a[index]!=invalid){root=new Node(a[index]);_CreateTree(root->leftchild,a,size,++index,invalid);_CreateTree(root->rightchild,a,size,++index,invalid);}}void _InOrderThead(Node* root,Node* &pre){     if(root==NULL) return ; _InOrderThead(root->leftchild,pre); if(root->leftchild==NULL) { root->LeftTag=Thread; root->leftchild=pre; } if(pre&&pre->rightchild==NULL) { pre->RightTag=Thread; pre->rightchild=root; } pre=root; _InOrderThead(root->rightchild,pre);}private:Node* _root;};

测试用例

void test(){int a1[10]={1,2,3,'#','#',4,'#','#',5,6};BinTree<int> t1(a1,10,'#');t1.InOrderThead();//t1.InOrder_NonR();BinTree<int>::Iterator it=t1.Begin();cout<<endl;while (it!=t1.End()){cout<<*it<<" ";++it;}cout<<endl;}

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