// C# program for different  

// tree traversals 

using System;  

/* Class containing left and  

right child of current 

node and key value*/

public class Node 

{ 

    public int key; 

    public Node left, right; 

    public Node(int item) 

    { 

        key = item; 

        left = right = null; 

    } 

} 

public class BinaryTree 

{ 

// Root of Binary Tree 

Node root; 

BinaryTree() 

{ 

    root = null; 

} 

/* Given a binary tree, print  

   its nodes according to the 

   "bottom-up" postorder traversal. */

void printPostorder(Node node) 

{ 

    if (node == null) 

        return; 

    // first recur on left subtree 

    printPostorder(node.left); 

    // then recur on right subtree 

    printPostorder(node.right); 

    // now deal with the node 

    Console.Write(node.key + " "); 

} 

/* Given a binary tree, print  

   its nodes in inorder*/

void printInorder(Node node) 

{ 

    if (node == null) 

        return; 

    /* first recur on left child */

    printInorder(node.left); 

    /* then print the data of node */

    Console.Write(node.key + " "); 

    /* now recur on right child */

    printInorder(node.right); 

} 

/* Given a binary tree, print 

   its nodes in preorder*/

void printPreorder(Node node) 

{ 

    if (node == null) 

        return; 

    /* first print data of node */

    Console.Write(node.key + " "); 

    /* then recur on left sutree */

    printPreorder(node.left); 

    /* now recur on right subtree */

    printPreorder(node.right); 

} 

// Wrappers over above recursive functions 

void printPostorder() {printPostorder(root);} 

void printInorder()  {printInorder(root);} 

void printPreorder() {printPreorder(root);} 

// Driver Code 

static public void Main(String []args) 

{ 

    BinaryTree tree = new BinaryTree(); 

    tree.root = new Node(1); 

    tree.root.left = new Node(2); 

    tree.root.right = new Node(3); 

    tree.root.left.left = new Node(4); 

    tree.root.left.right = new Node(5); 

    Console.WriteLine("Preorder traversal " +  

                       "of binary tree is "); 

    tree.printPreorder(); 

    Console.WriteLine("\nInorder traversal " +   

                        "of binary tree is "); 

    tree.printInorder(); 

    Console.WriteLine("\nPostorder traversal " +  

                          "of binary tree is "); 

    tree.printPostorder(); 

} 

} 

// This code is contributed by Arnab Kundu 

​

/*Output:

Preorder traversal of binary tree is

1 2 4 5 3 

Inorder traversal of binary tree is

4 2 5 1 3 

Postorder traversal of binary tree is

4 5 2 3 1 */