What Is Tree Traversal in Data Structure?


Heather Bennett

Tree Traversal is a fundamental concept in data structures that involves visiting all the nodes of a tree in a specific order. It is an essential operation when working with trees, as it allows us to access and process each node efficiently.

Types of Tree Traversal

There are three main types of tree traversal:

1. Inorder Traversal

In inorder traversal, we visit the left subtree, then the root node, and finally the right subtree. It follows the Left-Root-Right order.


  • Visit the left subtree
  • Visit the root node
  • Visit the right subtree

2. Preorder Traversal

In preorder traversal, we visit the root node first, followed by its left subtree, and then its right subtree. It follows the Root-Left-Right order.


  • Visit the root node
  • Visit the left subtree
  • Visit the right subtree

3. Postorder Traversal

In postorder traversal, we visit the left subtree first, then the right subtree, and finally the root node. It follows the Left-Right-Root order.


  • Visit the left subtree
  • Visit the right subtree
  • Visit the root node

The Importance of Tree Traversal

Tree traversal is crucial for various applications involving trees:

  • Searching and Sorting: Tree traversal algorithms are used in searching for elements within a tree or sorting the elements in a specific order.
  • Expression Evaluation: In certain contexts, trees are used to represent mathematical expressions. Traversing such trees allows us to evaluate the expressions correctly.
  • Constructing Trees: Traversal techniques help in constructing trees from given data, such as creating a binary search tree from a sorted list of elements.
  • Tree Manipulation: By traversing a tree, we can modify or update its nodes based on specific requirements.

Implementing Tree Traversal

To implement tree traversal, we typically use recursion. Here’s an example of implementing inorder traversal in Python:

class Node:
    def __init__(self, value):
        self.value = value
        self.left = None
        self.right = None

def inorder_traversal(node):
    if node is not None:

# Usage
root = Node(1)
root.left = Node(2)
root.right = Node(3)


This code snippet demonstrates how we can recursively traverse a binary tree using the inorder traversal technique. Similar implementations can be done for preorder and postorder traversals.


Tree traversal is an essential concept in data structures that allows us to visit and process each node of a tree efficiently. Understanding different types of tree traversals and their applications is crucial for effectively working with trees and solving various problems related to them.

Note: It’s important to note that the examples and code snippets provided in this article are for illustrative purposes. Actual implementation may vary depending on the programming language and specific requirements.

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