#include <iostream>
#include <string>
#include <vector>
#include <stack>
#include <stdio.h>
#include <time.h>

using namespace std;

struct Node
{
  int data;      // 节点中的数据
  Node *m_pLeft;
  Node *m_pRight;
};

Node* CreatNode(int value)
{
  Node* pNode = new Node;
  pNode->data = value;
  return pNode;
}

void ConnectNodes(Node* pParent, Node* pLeft, Node* pRight)
{
  if (pParent != nullptr)
  {
    pParent->m_pLeft = pLeft;
    pParent->m_pRight = pRight;
  }
}


void PrintNodeByLevel(Node* root)
{
  if (root == nullptr)
  {
    return;
  }

  vector<Node*> NodeVec;
  NodeVec.push_back(root);

  int cur = 0;
  int last = 1;

  while (cur < NodeVec.size())//更新cur
  {
    last = NodeVec.size();//更新last
    while (cur < last)//当前层的遍历输出
    {
      cout << NodeVec[cur]->data << " ";
      if (NodeVec[cur]->m_pLeft)
      {
        NodeVec.push_back(NodeVec[cur]->m_pLeft);
      }
      if (NodeVec[cur]->m_pRight)
      {
        NodeVec.push_back(NodeVec[cur]->m_pRight);
      }
      cur++;
    }
    cout << endl;
  }
}

int main()
{
  //            1
  //          /   \
  //        2      3
  //       /  \      \
  //      4   5       6
  //         /  \
  //        7    8
  Node *pNode1 = CreatNode(1);
  Node *pNode2 = CreatNode(2);
  Node *pNode3 = CreatNode(3);
  Node *pNode4 = CreatNode(4);
  Node *pNode5 = CreatNode(5);
  Node *pNode6 = CreatNode(6);
  Node *pNode7 = CreatNode(7);
  Node *pNode8 = CreatNode(8);

  ConnectNodes(pNode1, pNode2, pNode3);
  ConnectNodes(pNode2, pNode4, pNode5);
  ConnectNodes(pNode5, pNode7, pNode8);
  ConnectNodes(pNode3, nullptr, pNode6);
  ConnectNodes(pNode4, nullptr, nullptr);
  ConnectNodes(pNode6, nullptr, nullptr);
  ConnectNodes(pNode7, nullptr, nullptr);
  ConnectNodes(pNode8, nullptr, nullptr);

  PrintNodeByLevel(pNode1);

  return 0;
}

分层遍历二叉树_遍历