typedef struct _BiTNode 
{ 
  int data; 
  _BiTNode *leftChild; 
  _BiTNode *rightChild; 
}BiTNode, *pBiTree; 

//创建二叉树, 先序顺序 
int CreateBiTree(pBiTree *root) 
{ 
  char ch = 0; 
  fflush(stdin); 
  if ((ch = getchar()) == 'a')//控制树的结构 
  { 
    *root = NULL; 
  } 
  else 
  { 
    *root = (BiTNode *)malloc(sizeof(BiTNode)); 
    if (!(*root)) 
    { 
      return RET_ERROR; 
    } 
    (*root)->data = GetRandom(); 
    CreateBiTree(&(*root)->leftChild); 
    CreateBiTree(&(*root)->rightChild); 
  } 
  return RET_OK; 
} 
 
int g_i = 0; 
//创建二叉树,自动执行，方便测试 
int CreateBiTreeAuto(pBiTree *root) 
{ 
  char szOrder[] = "bbaabaa"; 
  char ch = 0; 
  if (szOrder[g_i++] == 'a')//控制树的结构 
  { 
    *root = NULL; 
  } 
  else 
  { 
    *root = (BiTNode *)malloc(sizeof(BiTNode)); 
    if (!(*root)) 
    { 
      return RET_ERROR; 
    } 
    (*root)->data = GetRandom(); 
    CreateBiTreeAuto(&(*root)->leftChild); 
    CreateBiTreeAuto(&(*root)->rightChild); 
  } 
  return RET_OK; 
} 

//先序遍历 
int PreOrderVisitTree(pBiTree T, VisitType pFuncVisit) 
{ 
  if (T) 
  { 
    (*pFuncVisit)(T->data); 
    if (PreOrderVisitTree(T->leftChild, pFuncVisit) == RET_OK) 
    { 
      if (PreOrderVisitTree(T->rightChild, pFuncVisit) == RET_OK) 
      { 
        return RET_OK; 
      } 
    } 
    return RET_ERROR; 
  } 
  else 
  { 
    return RET_OK; 
  } 
} 

//中序遍历, 非递归实现 
int InOrderVisitTree(pBiTree T, VisitType pFuncVisit) 
{ 
  ponyStack binaryTreeStack; 
  InitStack(&binaryTreeStack, 4); 
  Push(&binaryTreeStack, &T); 
  pBiTree pTempNode; 
 
  while (!IsEmptyStack(binaryTreeStack)) 
  { 
    while((GetTop(binaryTreeStack, &pTempNode) == RET_OK) && (pTempNode != NULL)) 
    { 
      Push(&binaryTreeStack, &(pTempNode->leftChild)); 
    } 
    Pop(&binaryTreeStack, &pTempNode); 
    if (!IsEmptyStack(binaryTreeStack)) 
    { 
      Pop(&binaryTreeStack, &pTempNode); 
      (*pFuncVisit)(pTempNode->data); 
      Push(&binaryTreeStack, &(pTempNode->rightChild)); 
    } 
  } 
  return RET_OK; 
}