线索化二叉树C++

线索化二叉树
1.创建二叉树
2.先序递归遍历输出二叉树
3.线索化二叉树
4.输出线索化二叉树

/*线索化二叉树1.创建二叉树2.先序递归遍历输出二叉树3.线索化二叉树4.输出线索化二叉树*/#include<iostream>#include<stack>#include<string>#include<fstream>using namespace std;class Node{public:char data;bool ltag, rtag;class Node *lchild, *rchild;};class Thread_Binary_Tree{public:Thread_Binary_Tree(){}~Thread_Binary_Tree(){}//创建二叉树void create_binary_tree(string filename){ifstream readfile;string str;readfile.open(filename,ios::in);getline(readfile,str);cout << str << endl;Create_Tree(str);//创建二叉树readfile.close();}//先序递归输出二叉树void displayFront_tree(){cout << "先序递归输出" << endl;output_fro(t);//递归先序输出cout << endl;}//创建线索化二叉树void create_thread_Btree(){thread_root = CreateThread(t);}//输出线索化二叉树void display_thread_Btree(){cout << "中序线索化输出" << endl;output_thread(thread_root);cout << endl;cout << "中序线索化新根节点左右标记" << endl;cout << thread_root->ltag << "," << thread_root->rtag << endl;//输出中序线索化新根节点左右标记}private:Node *t;Node *pre;Node *thread_root;//创建二叉树void Create_Tree(string str){stack<Node *> m_stack;int k;Node *p;while (!str.empty()){if (str[0] == '('){m_stack.push(p);k = 1;}else if (str[0] == ')')//必须使用if-else if{m_stack.pop();}else if (str[0] == ','){k = 2;}else{p = (Node *)malloc(sizeof(Node));p->lchild = p->rchild = NULL;p->data = str[0];//将串首字符赋给dataif (t == NULL)//处理根节点{t = p;}else{if (k == 1){m_stack.top()->lchild = p;//左子树}if (k == 2){m_stack.top()->rchild = p;//右子树}}}str.assign(str.substr(1, str.length() - 1));//构建新串，将串首字符除去}}//先序递归输出二叉树void output_fro(Node *t){if (t == NULL){return;}else{cout << t->data;if (t->lchild != NULL || t->rchild != NULL){cout << "(";output_fro(t->lchild);//先序递归左子树if (t->rchild != NULL){cout << ",";}output_fro(t->rchild);//先序递归右子树cout << ")";}}}//中序线索化二叉树void Thread(Node *&p){if (p != NULL){Thread(p->lchild);//向左直走if (p->lchild == NULL)//遍历到中序遍历输出的首节点且无左子节点{p->lchild = pre;//指向前驱节点p->ltag = true;}else//存在左子节点{p->ltag = false;}if (pre->rchild == NULL)//若右节点无子节点,则右指针指向后继节点{pre->rchild = p;pre->rtag = true;}else//存在右子节点{pre->rtag = false;}pre = p;//更新Thread(p->rchild);//处理右子树}}//创建线索化二叉树Node *CreateThread(Node *t){Node *root;root = (Node *)malloc(sizeof(Node));//生成附加根节点root->ltag = false; root->rtag = true;root->rchild = t;if (t == NULL)//空树线索化{root->lchild = root;}else{root->lchild = t;pre = root;//pre初始化Thread(t);//线索化二叉树pre->rchild = root;//中序末节点pre->rtag = true;root->rchild = pre;//新生成根节点root->rtag = 1;//新生成根节点rtag=1；}return root;}//遍历输出线索化二叉树void output_thread(Node *t){Node *p = t->lchild;while (p != t){while (!p->ltag){p = p->lchild;}cout << p->data << ends;while (p->rtag&&p->rchild != t){p = p->rchild;cout << p->data << ends;}p = p->rchild;}}};int main(){Thread_Binary_Tree m_tree;m_tree.create_binary_tree("data");//创建普通二叉树m_tree.displayFront_tree();//先序递归遍历输出m_tree.create_thread_Btree();//创建中序线索化二叉树m_tree.display_thread_Btree();//输出中序线索化二叉树return 0;}

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