17-- 从上到下打印二叉树，按层打印。

//
//  main.cpp
//  subStructureInTree
//
//  Created by Hugo Cao  on 15/7/10.
//  Copyright (c) 2015年 Hugo Cao . All rights reserved.
//

/*
问题描述：
从上到下打印二叉树，按层打印。
思路：这里用队列实现了转化。很有意思的想法。

*/

#include <iostream>
#include <deque>
using namespace std;
#define Data int

typedef struct binaaryTreeNode
{
Data m_value;
binaaryTreeNode *m_pleft;
binaaryTreeNode *m_pright;
}btNode, *binTree;

binTree addNode(Data value)
{
binTree bt = NULL;
bt = new btNode;
if (bt == NULL)
{
cout << "申请地址错误" << endl;
return NULL;
}

bt->m_value = value;
bt->m_pleft = NULL;
bt->m_pright = NULL;

return bt;
}

bool connectTreeNode(binTree parrentNode, binTree leftSonNode = NULL, binTree rightSonNode = NULL)
{
if (parrentNode == NULL || (leftSonNode == NULL && rightSonNode == NULL))
{
cout << "结点输入问题" << endl;
return false;
}
parrentNode->m_pleft  = leftSonNode;
parrentNode->m_pright = rightSonNode;
return true;
}

binTree createBinaryATree(binTree Ahead)
{
binTree p1 = addNode(8);
binTree p2 = addNode(8);
binTree p3 = addNode(7);
binTree p4 = addNode(9);
binTree p5 = addNode(2);
binTree p6 = addNode(4);
binTree p7 = addNode(7);

connectTreeNode(p1, p2, p3);
connectTreeNode(p2, p4, p5);
connectTreeNode(p5, p6, p7);

return (Ahead = p1);
}

//按层打印
void PrintFromTopToButtom(binTree bt)
{
//如果是空结点就退出
if (!bt)
{
return ;
}
//使用队列作为模型
deque<binTree> dequeTreeNode;
dequeTreeNode.push_back(bt);    //将根结点压入队列

//栈为空的时候退出循环
while (dequeTreeNode.size())
{
//返回队列头指针
binTree pNode = dequeTreeNode.front();
printf("%d\n", pNode->m_value);     //打印向量信息
dequeTreeNode.pop_front();          //弹出

//层遍历，其实也是先左后右，向队列压入元素。
if (pNode->m_pleft)
{
dequeTreeNode.push_back(pNode->m_pleft);
}
if (pNode->m_pright)
{
dequeTreeNode.push_back(pNode->m_pright);
}
}

}

//打印二叉树
void BLR_print_BinaryTree(binTree bt)
{
if (bt == NULL)
return ;

cout << bt->m_value << "  " << endl;
BLR_print_BinaryTree(bt->m_pleft);
BLR_print_BinaryTree(bt->m_pright);
}

int main()
{
binTree bt_A = NULL;
bt_A = createBinaryATree(bt_A);
PrintFromTopToButtom(bt_A);
cout << endl;

return 0;
}