#include <stdio.h>
#include <malloc.h>
#define OK 1
#define ERROR 0
/////////////////////////二叉树的二叉链表节点结构
typedef struct Node
{
    char data;
    struct Node * LChild;
    struct Node * RChild;
}BiTNode, * BiTree;

int CreateBiTree(BiTree T)//建立二叉树
{
    char ch;
    ch=getchar();
    if(ch==' ')
        T=NULL;
    else
    {
        if (!(T=(BiTNode *)malloc(sizeof(BiTNode))))
            return ERROR;
        T->data=ch;
        CreateBiTree(T->LChild);
        CreateBiTree(T->RChild);
    }
    return OK;
}


void  PreOrder(BiTree root)
/*先序遍历二叉树, root为指向二叉树(或某一子树)根结点的指针*/
{
    if (root!=NULL)
    {
        printf("%c",root ->data);  /*访问根结点*/
        PreOrder(root ->LChild);  /*先序遍历左子树*/
        PreOrder(root ->RChild);  /*先序遍历右子树*/
    }
}




int main()
{
    BiTree Tree;
    CreateBiTree(Tree);
    PreOrder(Tree);
    return 0;
}


在执行printf("%c",root ->data);  /*访问根结点*/
出现问题，哪里错了呢

#include <stdio.h>
#include <malloc.h>
#define OK 1
#define ERROR 0
/////////////////////////二叉树的二叉链表节点结构
typedef struct Node
{
    char data;
    struct Node * LChild;
    struct Node * RChild;
}BiTNode, * BiTree;

BiTree CreateBiTree(BiTree T)//建立二叉树
{
    char ch;
    ch=getchar();
    if(ch==' ')
        T=NULL;
    else
    {
        if (!(T=(BiTNode *)malloc(sizeof(BiTNode))))
            return ERROR;
        T->data=ch;
        CreateBiTree(T->LChild);
        CreateBiTree(T->RChild);
    }
    return T;
}


void  PreOrder(BiTree root)
/*先序遍历二叉树, root为指向二叉树(或某一子树)根结点的指针*/
{
    if (root!=NULL)
    {
        printf("%c",root ->data);  /*访问根结点*/
        PreOrder(root ->LChild);  /*先序遍历左子树*/
        PreOrder(root ->RChild);  /*先序遍历右子树*/
    }
}




int main()
{
    BiTree Tree;
    Tree=CreateBiTree(Tree);
    PreOrder(Tree);
    return 0;
}

自己改了下，这下只能打印一个字符，搞不懂为什么