线索化二叉树代码实现（细！！）

中序线索化二叉树

#include <stdio.h>
#include <stdlib.h>
//定义二叉链表
typedef struct ThreadNode{
    int data;
    struct ThreadNode *lchild,*rchild; //左、右孩子指针
    int ltag,rtag; //线索标志位：值为1表示指针为线索，值为0表示指针指向孩子
}ThreadNode,*ThreadTree;
//全局变量，指向前驱结点
ThreadNode *pre=NULL;
//线索化
void visit(ThreadNode *p){
    if(p->lchild==NULL){
        p->lchild=pre;
        p->ltag=1;
    }
    if(pre!=NULL&&pre->rchild==NULL){
        pre->rchild=p;
        pre->rtag=1;
    }
    pre=p;
    printf("%d、",p->data);
};
//中续遍历
void MiddleOrder(ThreadTree T){
    if(T!=NULL){
        MiddleOrder(T->lchild);
        visit(T);//遍历过程中线索化
        MiddleOrder(T->rchild);
    }
};
//中序线索化二叉树
void CreatThreadTree(ThreadTree T){
    pre=NULL;
    if(T!=NULL){
        MiddleOrder(T);
        pre->rtag=1;
    }
};
int main () {
    //定义一个空二叉树
    ThreadTree T = NULL;
    //初始化
    T = (ThreadTree) malloc(sizeof(ThreadNode));
    T->data = 1;
    T->lchild = NULL;
    T->rchild = NULL;
    printf("根节点data=%d\n",T->data);
    //将2插入到左孩子;
    ThreadNode * p1 = (ThreadNode *)malloc(sizeof(ThreadNode));
    p1->data = 2;
    p1->lchild = NULL;
    p1->rchild = NULL;
    T->lchild = p1;
    printf("根节点左孩子data=%d\n",T->lchild->data);
     //将3插入到又孩子;
    ThreadNode * p2 = (ThreadNode *)malloc(sizeof(ThreadNode));
    p2->data = 3;
    p2->lchild = NULL;
    p2->rchild = NULL;
    T->rchild = p2;
    printf("根节点右孩子data=%d\n",T->rchild->data);
    printf("中续遍历：\n");
    CreatThreadTree(T);
    printf("\n线索化成功！");
    return 0;
}  

先续线索化 二叉树

#include <stdio.h>
#include <stdlib.h>
//定义二叉链表
typedef struct ThreadNode{
    int data;
    struct ThreadNode *lchild,*rchild; //左、右孩子指针
    int ltag,rtag; //线索标志位：值为1表示指针为线索，值为0表示指针指向孩子
}ThreadNode,*ThreadTree;
//全局变量，指向前驱结点
ThreadNode *pre=NULL;
//线索化
void visit(ThreadNode *p){
    if(p->lchild==NULL){
        p->lchild=pre;
        p->ltag=1;
    }
    if(pre!=NULL&&pre->rchild==NULL){
        pre->rchild=p;
        pre->rtag=1;
    }
    pre=p;
    printf("%d、",p->data);
};
//先续遍历
void PreOrder(ThreadTree T){
    if(T!=NULL){
        visit(T);//遍历过程中线索化
        if(T->ltag==0)//防止转圈问题
            PreOrder(T->lchild);
        PreOrder(T->rchild);
    }
};
//先序线索化二叉树
void CreatThreadTree(ThreadTree T){
    pre=NULL;
    if(T!=NULL){
        PreOrder(T);
        pre->rtag=1;
    }
};
int main () {
    //定义一个空二叉树
    ThreadTree T = NULL;
    //初始化
    T = (ThreadTree) malloc(sizeof(ThreadNode));
    T->data = 1;
    T->lchild = NULL;
    T->rchild = NULL;
    printf("根节点data=%d\n",T->data);
    //将2插入到左孩子;
    ThreadNode * p1 = (ThreadNode *)malloc(sizeof(ThreadNode));
    p1->data = 2;
    p1->lchild = NULL;
    p1->rchild = NULL;
    T->lchild = p1;
    printf("根节点左孩子data=%d\n",T->lchild->data);
     //将3插入到又孩子;
    ThreadNode * p2 = (ThreadNode *)malloc(sizeof(ThreadNode));
    p2->data = 3;
    p2->lchild = NULL;
    p2->rchild = NULL;
    T->rchild = p2;
    printf("根节点右孩子data=%d\n",T->rchild->data);
    printf("先续遍历：\n");
    CreatThreadTree(T);
    printf("\n线索化成功！");
    return 0;
}  

 后续线索化二叉树

#include <stdio.h>
#include <stdlib.h>
//定义二叉链表
typedef struct ThreadNode{
    int data;
    struct ThreadNode *lchild,*rchild; //左、右孩子指针
    int ltag,rtag; //线索标志位：值为1表示指针为线索，值为0表示指针指向孩子
}ThreadNode,*ThreadTree;
//全局变量，指向前驱结点
ThreadNode *pre=NULL;
//线索化
void visit(ThreadNode *p){
    if(p->lchild==NULL){
        p->lchild=pre;
        p->ltag=1;
    }
    if(pre!=NULL&&pre->rchild==NULL){
        pre->rchild=p;
        pre->rtag=1;
    }
    pre=p;
    printf("%d、",p->data);
};
//后续遍历
void PostOrder(ThreadTree T){
    if(T!=NULL){
        PostOrder(T->lchild);
        PostOrder(T->rchild);
        visit(T);//遍历过程中线索化
    }
};
//后序线索化二叉树
void CreatThreadTree(ThreadTree T){
    pre=NULL;
    if(T!=NULL){
        PostOrder(T);
        pre->rtag=1;
    }
};
int main () {
    //定义一个空二叉树
    ThreadTree T = NULL;
    //初始化
    T = (ThreadTree) malloc(sizeof(ThreadNode));
    T->data = 1;
    T->lchild = NULL;
    T->rchild = NULL;
    printf("根节点data=%d\n",T->data);
    //将2插入到左孩子;
    ThreadNode * p1 = (ThreadNode *)malloc(sizeof(ThreadNode));
    p1->data = 2;
    p1->lchild = NULL;
    p1->rchild = NULL;
    T->lchild = p1;
    printf("根节点左孩子data=%d\n",T->lchild->data);
     //将3插入到又孩子;
    ThreadNode * p2 = (ThreadNode *)malloc(sizeof(ThreadNode));
    p2->data = 3;
    p2->lchild = NULL;
    p2->rchild = NULL;
    T->rchild = p2;
    printf("根节点右孩子data=%d\n",T->rchild->data);
    printf("后续遍历：\n");
    CreatThreadTree(T);
    printf("\n线索化成功！");
    return 0;
}  

点赞收藏哟~