诡异的二叉树的中序遍历二

void mid2_order (BTreeNode *node)
{
if (node == NULL)
{
errno = ERROR;
return;
}
LinkStack *Stack = Create_Stack ();
BTreeNode *tmp = node;   //指向当前节点
while (tmp)
{
Push (Stack,tmp);
if (tmp->lchild)
{
tmp = tmp->lchild;
continue;
}
tmp = tmp->rchild;
while(tmp == NULL && Pop (Stack,&tmp))
{
printf("%4c",tmp->data);
tmp = tmp->rchild;
}
}
}