输入一颗二元树，从上往下按层打印树的每个结点，同一层中按照从左往右的顺序打印。

题目（微软）：
输入一颗二元树，从上往下按层打印树的每个结点，同一层中按照从左往右的顺序打印。
例如输入
8
/ /
6 10
/ / / /
5 7 9 11

输出8 6 10 5 7 9 11。

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C# codes as below:

using System;

using System.Collections.Generic;

namespace ConsoleApp

{

class RunClass

{

static void Main()

{

Node<int> i1 = new Node<int>() { Value = 4 };

Node<int> i2 = new Node<int>() { Value = 8 };

Node<int> i3 = new Node<int>() { Value = 12};

Node<int> i4 = new Node<int>() { Value = 16};

Node<int> i5 = new Node<int>() { Value = 6, Left = i1, Right = i2 };

Node<int> i6 = new Node<int>() { Value = 14, Left = i3, Right = i4 };

Node<int> i7 = new Node<int>() { Value = 10, Left = i5, Right = i6 };

Tree<int> tree = new Tree<int> { Root = i7 };

new Helper().PrintTree<int>(tree);

Console.ReadLine();

}

}

class Helper

{

public void PrintTree<T>(Tree<T> tree)

{

Node<T> root=tree.Root;

Queue<Node<T>> queue = new Queue<Node<T>>();

queue.Enqueue(root);

while (queue.Count != 0)

{

Node<T> node = queue.Dequeue();

Console.WriteLine(node.Value);

if (node.Left != null)

queue.Enqueue(node.Left);

if (node.Right != null)

queue.Enqueue(node.Right);

}

}

}

class Tree<T>

{

public Node<T> Root { get; set; }

}

class Node<T>

{

public Node<T> Left { get; set; }

public Node<T> Right { get; set; }

public T Value { get; set; }

}

}