二叉树

#include<stdio.h>#include<stdlib.h>typedef struct bitree //封装一个二叉树的结构体{    int data;    struct bitree *lchild;    struct bitree *rchild;}bitree_t;struct node {    bitree_t *data;    struct node *next;};typedef struct        // 封装一个队列，为了层次遍历而使用{    struct node *front;    struct node *rear;}linkqueue;bitree_t *create_bitree(int num,int max)//递归创建二叉树{    bitree_t *curnode;    if(num > max)//递归的退出条件        return NULL;    curnode = (bitree_t *)malloc(sizeof(bitree_t));    curnode->data = num;    curnode->lchild = create_bitree(2 * num,max);    curnode->rchild = create_bitree(2 * num + 1,max);    return curnode;}int pre_traverse(bitree_t *curnode)//先序递归遍历二叉树{    if(curnode == NULL)    {        return -1;    }    printf("%d ",curnode->data);    pre_traverse(curnode->lchild);    pre_traverse(curnode->rchild);    return 0;}int mid_traverse(bitree_t *curnode)//中序递归遍历二叉树{    if(curnode == NULL)        return -1;    mid_traverse(curnode->lchild);    printf("%d ",curnode->data);    mid_traverse(curnode->rchild);    return 0;}int last_traverse(bitree_t *curnode)//后续递归遍历二叉树{    if(curnode == NULL)        return -1;    last_traverse(curnode->lchild);    last_traverse(curnode->rchild);    printf("%d ",curnode->data);}linkqueue *create_empty_queue() //创建一个空的队列{    struct node *head;    head = (struct node *)malloc(sizeof(struct node));    head->next = NULL;    linkqueue *q;    q = (linkqueue *)malloc(sizeof(linkqueue));    q->front = q->rear = head;    return q;}int enter_queue(linkqueue *q,bitree_t *curnode)//将二叉树节点首地址入队{    struct node *temp;    temp = (struct node *)malloc(sizeof(struct node));    temp->data = curnode;    q->rear->next = temp;    temp->next = NULL;    q->rear = temp;    return 0;}int is_queue_empty(linkqueue *q)//判断队列是否为空{    return q->front == q->rear ? 1 : 0;}bitree_t *out_queue(linkqueue *q)//将二叉树节点首地址出队{    if(is_queue_empty(q))    {        printf("empty\n");        return NULL;    }    struct node *temp;    temp = q->front;    q->front = temp->next;    free(temp);    return q->front->data;}int lelvel_traverse(bitree_t *curnode)//层次遍历{    linkqueue *q;    q = create_empty_queue();    enter_queue(q,curnode);    while(!is_queue_empty(q))    {        curnode = out_queue(q);        printf("%d ",curnode->data);        if(curnode->lchild != NULL)            enter_queue(q,curnode->lchild);        if(curnode->rchild != NULL)            enter_queue(q,curnode->rchild);    }}int main(int argc, const char *argv[]){    bitree_t *curnode;#if 0       申请一个空间作为某个节点的首地址    数据赋值    给左孩子申请空间    赋值    给右孩子申请空间    赋值    bitree_t *root;    root = (bitree_t *)malloc(sizeof(bitree_t));    root->data = 1;    //p代表左孩子地址    p = malloc(sizeof(bitree_t));    p->data = 2;    {        //q是p的左孩子        p->lchild = malloc(sizeof(bitree_t));        q->data = 数值        //x是p的右孩子        p->rchild = malloc(sizeof(bitree_t));        x->data = 数值    }    //代表根的右孩子    pr = malloc(sizeof(bitree_t));    pr->data = 数值;    {        pr->lchild = malloc();        pr->rchild = malloc();    }#endif 上面注释的是递归的思想    curnode = create_bitree(1,6);//完全二叉树的初始编号是1，一共有6个节点    pre_traverse(curnode);    printf("\n");    mid_traverse(curnode);    printf("\n");    last_traverse(curnode);    printf("\n");    lelvel_traverse(curnode);    printf("\n");    return 0;}