Write a program to Convert a binary tree to doubly linked list.

Binary tree is a tree data structure in which each node has at most two children, which are referred to as the left child and the right child.

Wikipedia

#### Solution

```
using System;
namespace LinkedListOpearation
{
class Program
{
public static void Main(string[] args)
{
var linkedList = new DoublyLinkedList
{
Root = new Node(10) {Left = new Node(12), Right = new Node(15)}
};
linkedList.Root.Left.Left = new Node(25);
linkedList.Root.Left.Right = new Node(30);
linkedList.Root.Right.Left = new Node(36);
linkedList.ConvertBinaryTreeToLinkedList(linkedList.Root);
linkedList.Print(linkedList.Head);
Console.ReadLine();
}
}
class DoublyLinkedList
{
public Node Root;
public Node Head;
public static Node Prev;
public virtual void ConvertBinaryTreeToLinkedList(Node root)
{
if (root == null)
return;
ConvertBinaryTreeToLinkedList(root.Left);
if (Prev == null)
{
Head = root;
}
else
{
root.Left = Prev;
Prev.Right = root;
}
Prev = root;
ConvertBinaryTreeToLinkedList(root.Right);
}
public void Print(Node node)
{
while (node != null)
{
Console.WriteLine(node.Data);
node = node.Right;
}
}
}
public class Node
{
public int Data;
public Node Left;
public Node Right;
public Node(int data)
{
Data = data;
}
}
}
```