C++ 遍历二叉树的顺序是从上到下、自左而右

 #include <iostream>

    
 #include "BinaryTree.h"
    
 #include <deque>
    
 using namespace std;
    
 void PrintTree_from_head_to_tail(TreeNode* proot)
    
 {
    
 	if(proot == NULL)
    
 		return;
    
 	deque <TreeNode*> tree_que;
    
 	TreeNode* node = proot;
    
 	tree_que.push_back(node);
    
 	while(!tree_que.empty())
    
 	{
    
 		node = tree_que.front();
    
 		if(node ->pLeft != NULL)
    
 			tree_que.push_back(node ->pLeft);
    
 		if(node ->pRight != NULL)
    
 			tree_que.push_back(node ->pRight);
    
 		cout << node->m_value <<'\t';
    
 		tree