请看一下我写的这段二叉树后续遍历非递归算法问题出在哪

C/C++ code

void PostOrderTraverse(BiTree T){    if(T){        Stack s;        InitStack(&s);        BiTree p;        BiTree q=NULL;        Push(&s,T);        while(!StackEmpty(s)){            while(Gettop(s,&p)&&p){                Push(&s,p->lchild);            }            Pop(&s,&p);            if(!StackEmpty(s)){                Gettop(s,&p);                if(p->rchild==NULL||p->rchild==q){                    Pop(&s,&p);                    printf("%c",p->data);                    q=p;                    p=NULL;                    Push(&s,p);                }                else                    p=p->rchild;            }        }    }}

C/C++ code

//3.后序遍历非递归算法#define maxsize 100typedef enum{L,R} tagtype;typedef struct {    Bitree ptr;    tagtype tag;}stacknode;typedef struct{    stacknode Elem[maxsize];    int top;}SqStack;
[解决办法]
C/C++ code
void PostOrderUnrec(Bitree t){    SqStack s;    stacknode x;    StackInit(s);    p=t;        do     {                    while (p!=null)        //遍历左子树        {                    x.ptr = p;             x.tag = L;         //标记为左子树            push(s,x);            p=p->lchild;        }
[解决办法]
C/C++ code
        while (!StackEmpty(s) && s.Elem[s.top].tag==R)          {                    x = pop(s);            p = x.ptr;            visite(p->data);                }                                 if (!StackEmpty(s))        {                    s.Elem[s.top].tag =R;            p=s.Elem[s.top].ptr->rchild;                }            }while (!StackEmpty(s));}//PostOrderUnrec