Postorder Tree Traversal in Binary Tree in C

A binary tree is a hierarchical data structure in computer science. Each node in a binary tree can have at most two children: a left child and a right child. There are several ways to traverse a binary tree and in this article, we will learn about the postorder traversal of a binary tree in C.

Example

Input:
 1 
 / \ 
 2 3 
 / \ / \ 
4 5 6 7

Output:
Postorder Traversal : 4 5 2 6 7 3 1

Postorder Tree Traversal in Binary Tree in C

The is a way of visiting all the nodes of a in a specific order. It involves visiting the left subtree first, followed by the right subtree, and finally the root node. Consider the below diagram to understand the workflow of postorder traversal:

Workflow of Postorder Traversal

Algorithm for Postorder Traversal in C

Following is the algorithm for the postorder traversal of the binary tree in C:

1. Start
2. Traverse left subtree using recursion.
3. Traverse right subtree using recursion
4. Visit the root node
5. Repeat steps 3-5 until root node != NULL
6. Stop

C Program for Postorder Traversal in a Binary Tree

The following program demonstrates how we can implement the postorder traversal in a binary tree in C:

Postorder traversal of the binary tree is:
4 5 2 6 7 3 1 

Time Complexity: O(N), where N denotes the number of nodes in the binary tree
Auxiliary Space: O(log N),if space of recursive stack is not considered. If the tree is skew, then O(N)

Applications of Postorder Traversal

Following are some use cases for the post-order traversal of a binary tree:

• Used to evaluate postfix expression.
• Used to convert mathematical expressions like infix to postfix conversion.
• Used to delete or free the memory occupied by a binary tree.
• Used in compiler design for code generation and optimization tasks.
• Used in the construction and traversal of threaded binary trees.

Related Articles

The following are some articles about the post order traveral of a binary tree that can improve your knowledge:

• Types of Tree traversals
• Postorder of Binary Tree without recursion and without stack
• Find Postorder traversal of BST from preorder traversal
• Iterative Postorder traversal (using two stacks)
• Iterative Postorder traversal (using one stack)