构造一直无法结束。。。。。。
#include<stdio.h>
#include<stdlib.h>
#define MAX_TREE_SiZE 100
#define TURE 1
#define FALSE 0
#define OK 1
#define ERROR 0
#define INFEASIBLE -1
#define OVERFLOW -2
typedef int Status;
typedef char TElemType;

typedef struct BiTNode
{
    TElemType data;
    struct BiTNode *lchild,*rchild;
}BiTNode;//二叉树
typedef struct BiTNode *BiTree;

void CreatBiTree(BiTree *T);
void PreOrderTraverse(BiTree T,Status(*Visit)(TElemType));
Status PrintElement(TElemType e);

int main()
{
    BiTree T;
    printf("先序输入二叉树：");
    CreatBiTree(&T);
    printf("先序输出二叉树：");
    PreOrderTraverse(T,PrintElement);
    return 0;
}
 
void CreatBiTree(BiTree *T)
{//先需输入二叉树
    char ch;
    scanf("%c",&ch);
    if(ch=='#')
        *T=NULL;
    else
    {
        (*T)=(BiTNode *)malloc(sizeof(BiTNode));
        if(!*T)
            exit(OVERFLOW);
        (*T)->data=ch;
        CreatBiTree(&(*T)->lchild);
        CreatBiTree(&(*T)->rchild);
    }
}

void PreOrderTraverse(BiTree T,Status(*Visit)(TElemType))
{//先序遍历二叉树，递归算法
    if(T)
    {
        Visit(T->data);
        PreOrderTraverse(T->lchild,Visit);
        PreOrderTraverse(T->rchild,Visit);
    }   
}


Status PrintElement(TElemType e)
{
        printf("%c ",e);
        return OK;
}