我的程序：#define _CRT_SECURE_NO_WARNINGS#include <stdio.h>#include <stdlib.h>#include <malloc.h>#include <string.h>#define OK 1#define ERROR -1#define OVERFLOW 0#define TRUE 1#define FALSE 0#define MAX_TREE_SIZE 100typedef int Status;typedef int TElemType;typedef struct BiTNode {TElemType data;struct BiTNode *lchild, *rchild;}BiTNode, *BiTree;Status CreateBiTree(BiTree &T) {char ch;scanf("%c", &ch);if (ch ==' ') T = NULL;else {if (!(T = (BiTNode*)malloc(sizeof(BiTNode)))) exit(OVERFLOW);T->data = ch;CreateBiTree(T->lchild);CreateBiTree(T->rchild);}return OK;}Status Visit(TElemType e){printf("%c\n", e);return OK;}Status PreOrderTraverse(BiTree T, Status (*Visit)(TElemType e)) {if (T) {if(Visit(T->data))if (PreOrderTraverse(T->lchild, Visit))if (PreOrderTraverse(T->rchild, Visit)) return OK;return ERROR;}else return OK;}int main(){BiTree T;CreateBiTree(T);printf("PreOrder is\n");PreOrderTraverse(T, Visit);system("pause");return 0;}我基本是完全按照課本寫的程序，可以編譯運行，但是輸入數據的時候不管輸多少個空格似乎都沒有辦法結束這個步驟開始遍歷，請問這是為什么？要如何修改？