二叉树的层次遍历，从上往下打印二叉树

struct BinaryTreeNode{int m_nValue;struct BinaryTreeNode *m_nLeft, *m_nRight;};void PrintTopToBottomAndLeftToRight(BinaryTreeNode *pTreeRoot){if (!pTreeRoot)return;std::deque<BinaryTreeNode *> dequeTreeNode;while (dequeTreeNode.size()){BinaryTreeNode *pNode = dequeTreeNode.front();dequeTreeNode.pop_front();cout << pNode->m_nValue;if (pNode->m_nLeft)dequeTreeNode.push_back(pNode->m_nLeft);if (pNode->m_nRight)dequeTreeNode.push_back(pNode->m_nRight);}}