帮帮忙，非递归算法先序建立二叉链表，问题出在哪里呢？

#define STACK_INIT_SIZE 100//测试值：abc@@de@g@@f@@@
#define STACKINCREMENT  10
#include <stdio.h>
#include <stdlib.h>
typedef char TElemType;

//////////////////////////////////////////////栈定义
typedef struct BiTNode
{
    TElemType data;
    struct BiTNode *lchild,*rchild;//
}BiTNode,*BiTree;
typedef struct
{
    BiTree *base;
    BiTree *top;
    int stacksize;
}SqStack;
/////////////////////////////////////////////栈的基本操作
void initialStack(SqStack *s)
{
    s->base=(BiTree *)malloc(STACK_INIT_SIZE*sizeof(BiTree));
    if(!s->base) exit(0);
    s->top=s->base;
    s->stacksize=STACK_INIT_SIZE;
}
void Push(SqStack *s,BiTNode *e)
{
    if(s->top-s->base>=s->stacksize)
    {
        s->base=(BiTree *)realloc(s->base,(STACK_INIT_SIZE+STACKINCREMENT)*sizeof(BiTree));
        if(!s->base) exit(0);
        s->top=s->base+s->stacksize;
        s->stacksize+=STACKINCREMENT;
    }
    *(s->top)++=e;
}
void Pop(SqStack *s,BiTree *e)//////////////////
{
    if(s->top==s->base) exit(0);
    *e=*--(s->top);//
}
int GetTop(SqStack *s,BiTree *e)///////////////////
{
    if(s->top==s->base) return(0);
    *e=*(s->top-1);//
    return(1);
}
int StackEmpty(SqStack *s)
{
    if(s->base==s->top)
        return(1);
    else
        return(0);
}
void ClearStack(SqStack *s)
{
    s->top=s->base;
    s->stacksize=0;
}
void DestoryStack(SqStack *s)
{
    free(s->base);
    s->stacksize=0;
}
BiTree CreatBiTree()//非递归算法先序建立二叉链表
{
    TElemType ch;
    BiTree T,p;
    SqStack S;
    initialStack(&S);
    scanf("%c",&ch);
    if(ch==' ')
        T=NULL;
    else
    {
        T=(BiTree)malloc(sizeof(BiTNode));
        T->data=ch;
        T->lchild=T->rchild=NULL;
        Push(&S,T);
    }
     while(!StackEmpty(&S))
     {
         scanf("%c",&ch);
         if(ch!=' ')//生成左儿子，直到左儿子为空时退出循环
         {
             p=(BiTree)malloc(sizeof(BiTNode));
             p->data=ch;
             p->lchild=p->rchild=NULL;
             T->lchild=p;
             T=p;
             Push(&S,T);
             scanf("%c",&ch);
         }
         else
             Pop(&S,&T);//弹出最后一个左儿子(栈顶元素)
         T->lchild=NULL;
         scanf("%c",&ch);
         if(ch==' ')//右儿子为空的情况
         {
             while((ch==' ')&&(!StackEmpty(&S)))//弹出栈顶元素，逆向返回，直到右儿子不为空
             {
                 T->rchild=NULL;
                 Pop(&S,&T);//弹出根结点，进入右子树
                 scanf("%c",&ch);
             }
             p=(BiTree)malloc(sizeof(BiTNode));
             p->data=ch;
             p->lchild=p->rchild=NULL;
             T->rchild=p;//右儿子的根结点p的父亲为T
             T=p;
             Push(&S,T);
         }
         else//右儿子不为空的情况
         {
             p=(BiTree)malloc(sizeof(BiTNode));
             p->data=ch;
             p->lchild=p->rchild=NULL;
             T->rchild=p;//右儿子的根结点p的父亲为T
             T=p;
             Push(&S,T);
         }
     }
     return T;
}   
void Visit(TElemType e)//对数据元素进行操作的Visit函数
{
    printf("%c",e);
}
void PreOrderTraverse(BiTree T)//先序遍历
{
    if(T)
    {
        Visit(T->data);
        PreOrderTraverse(T->lchild);
        PreOrderTraverse(T->rchild);
    }
}
/////////////////////////////////
void main()
{
    BiTree t;
    printf("请按先序遍历序列输入二叉树中各个结点的值(字符)，若为空树时输入空格键:\n");
    printf("<参考数据:abc@@de@g@@f@@@，则用空格键表示@，输完后再输入一个回车键.>\n");
    t=CreatBiTree();
    printf("[先序遍历]:\n");
    PreOrderTraverse(t);
    printf("\n");
}