二叉树遍历的还原

#include<stdio.h>
#include<string.h>
#include<stdlib.h>

typedef struct node
{
       char data;
       struct node *lchild;
       struct node *rchild;
}BiTNode,*BiTree;

BiTree tree(char *in,char *post,int len_in) 
{
BiTree t;
    int k;
    if(len_in<=0)
{
         t=NULL;
 return t;
    }
char *temp=in;
    for(;temp<in+len_in;temp++) /*在中序序列in中找到根节点所在的位置*/
{
         if(*(post+len_in-1)==*temp)
         {
              k=temp-in;  
              t=(BiTNode*)malloc(sizeof(BiTNode));
              t->data =*temp;
  break;
         }