中序和后序恢复二叉树问题
写了个恢复代码，思路觉得没有错，语法也没有错，执行的时候却出错了，调试了半天还是调不出来，请各位大虾帮帮忙，看下。
以前是我的代码：
#include<iostream>
using namespace std;
const int N=30;
struct node
{
char data;
struct node *lt,*rt;
};
void mid_post_creat(char *mid,char *post,int len,struct node **root)//len代表数组长度
{

char *m;
int k;
if(len<=0)
{
*root=NULL;
}
for(m=mid;m<mid+len;m++)
{
if(*m==*(post+len-1))
{
k=m-mid;
*root=new node;
(*root)->data=*(post+len-1);
break;
}
}
mid_post_creat(mid,post,k,&((*root)->lt));
mid_post_creat(mid+k+1,post+k,len-k-1,&((*root)->rt));
cout<<"恢复成功"<<endl;
}
int main()
{
struct node *root;
int len;
char mid[N]={NULL},post[N]={NULL};
cout<<"请输入中序序列"<<endl;
cin>>mid;
cout<<"请输入后序序列"<<endl;
cin>>post;
cout<<"请输入结点数"<<endl;
cin>>len;
void mid_post_creat(char *mid,char *post,int len,struct node **root);
mid_post_creat(mid,post,len,&root);
return 0;
}

[解决办法]

C/C++ code

#include<iostream>#include<cstdio>#include<cstring>using namespace std;struct BinaryTreeNode{    char c;    BinaryTreeNode *lchild, *rchild;    BinaryTreeNode()    {        lchild = NULL, rchild = NULL;    }};struct BinaryTreeNode *root;char preorder[100], inorder[100], postorder[100];void preSearch(BinaryTreeNode *root)   //先序遍历树{    if(root != NULL)    {        printf("%c", root->c);        preSearch(root->lchild);        preSearch(root->rchild);    }    return ;}void midSearch(BinaryTreeNode *root)   //中序遍历树{    if(root != NULL)    {        midSearch(root->lchild);        printf("%c", root->c);        midSearch(root->rchild);    }    return ;}void postSearch(BinaryTreeNode *root)  //后序遍历树{    if(root != NULL)    {        postSearch(root->lchild);        postSearch(root->rchild);        printf("%c", root->c);    }    return ;}void BuildTreeFromPostAndMid(BinaryTreeNode * &root, int ll, int lr, int len, int &now)//根据中序和后序求树{    root = new BinaryTreeNode();    root->c = *(postorder + now);    int pos = (int)(strchr(inorder, *(postorder + now)) - inorder);    now--;    if(now < 0)        return ;    if(pos + 1 <= lr)    {        BinaryTreeNode *t = new BinaryTreeNode();        root->rchild = t;        BuildTreeFromPostAndMid(root->rchild, pos + 1, lr, len, now);    }    if(pos - 1 >= ll)    {        BinaryTreeNode *t = new BinaryTreeNode();        root->lchild = t;        BuildTreeFromPostAndMid(root->lchild, ll, pos - 1, len, now);    }}//释放二叉树inline void DeleteBinaryTree(BinaryTreeNode * &root){    if(root)    {        DeleteBinaryTree(root->lchild);    //释放左子树        DeleteBinaryTree(root->rchild);    //释放右子树        delete root;          //释放根结点    }}int main(void){    gets(inorder);      //中序序列    gets(postorder);    //后序序列            int now = strlen(postorder)-1;    BuildTreeFromPostAndMid(root, 0, strlen(postorder) - 1, strlen(postorder), now);    preSearch(root);    DeleteBinaryTree(root);    puts("");    return 0;}