创建二叉树时，要把左右孩子的指针指向NULL，以防止样例出现野指针，从而运行错误；

#include<iostream>

using namespace std;

typedef struct node
{
    char data;
    struct node *lchild, *rchild;
}*Bitree;
string s;
int pos;
void CreatBitree(Bitree &T)
{
   if (pos >= s.size()) return;
	char c;
    c = s[pos++];
    if (c == '#') T = NULL;
    else
    {
        T = new node;
        T->data = c;
		T->lchild = NULL;//or will runing error
		T->rchild = NULL;//or will runing error
        CreatBitree(T->lchild);
        CreatBitree(T->rchild);
    }
}

void InOrder(Bitree T)
{
    if (T != NULL)
    {
        InOrder(T->lchild);
        cout << T->data << ' ';
        InOrder(T->rchild);
    }
}

int main()
{
    
    while (cin >> s)
    {
        Bitree T = NULL;
        pos = 0;
        CreatBitree(T);
        InOrder(T); cout << endl;

    }

    return 0;
}