中序线索二叉树的建立

#include<stdio.h> 
#include<stdlib.h>//中序建立二叉树 
typedef struct node
{
    struct node *left,*right;
    int data;
    int rTag,lTag;
}BNode;
BNode* pre=NULL;//pre总是指向其前一个结点 

BNode* CreateBTree()
{ 
int data, front=1, rear = 0; 
BNode *t, *root, *q[1001];
while(scanf("%d", &data), data!=-1)
{ 
   if(data==0) 
   t = NULL;
   else 
   { 
    t = (BNode*)malloc(sizeof(BNode));
    t->data = data;
    t->left = NULL; 
    t->right = NULL; 
   }
   q[++rear] = t;
     if(rear==1)
    root= t;
    else 
    {
    if(q[front]!=NULL) 
    { 
     if(rear%2==0)
     q[front]->left = t; 
     else 
     q[front]->right = t; 
    } 
     if(rear%2==1)
     front++;
     }
   } 
return root;
}


void InThreading(BNode*p)//如果某个结点的左孩子为空，则将空的左孩子指针域改为指向其前驱 
{ 
    if(p)//如果某结点的右孩子为空，则将空的右孩子指针域改为指向其后继 
{ 
     InThreading(p->left);
          if(!p->left)
           {
         p->lTag = 1;
         p->left = pre;//左孩子指向前驱
         } 
         if(pre && !pre->right)
          { 
          pre->rTag = 1; 
          pre->right = p;//右孩子指向后继 
          } 
      pre=p;//记住上一个结点 
      InThreading(p->right);
}
}
void InOrderThread(BNode* p)
 {
  while(p) 
  { 
   while(p->lTag==0) 
    p = p->left; 
    printf(" %d", p->data);
    while(p->rTag==1 && p->right!=NULL) 
    { 
      p = p->right; 
      printf(" %d", p->data); 
     } 
    p = p->right;
   } 
}

int main()
{
    BNode *root;
    root=CreateBTree();
    InThreading(root);
    InOrderThread(root);
    return 0;
}