Tree Traversal : Depth First Search in C

April 8, 2023

Tree Traversal : Depth First Search in C

Depth first search in C. DFS is an algorithm for traversing or searching tree data structures. The algorithm starts at the root node (selecting some arbitrary node as the root node in the case of a graph) and explores as far as possible along each branch before backtracking.

Here, in this page we will discuss the C program for DFS tree traversal.

Depth First Search (DFS) In C

Inorder Traversal : In inorder traversal, the left subtree is visited first, then the root and later the right sub-tree. Inorder traversal for the above example is 40 20 50 10 60 30 70.

Algorithm inorder(tree)

Recursively traverse left subtree.
Visit root node.
Recursively traverse right subtree.

Preorder Traversal : In preorder traversal , the root node is visited first, then the left subtree and finally the right subtree. Preorder Traversal for the above example is 10 20 40 50 30 60 70.

Algorithm preorder(Tree):

Visit root node.
Recursively traverse left subtree.
Recursively traverse right subtree.

Postorder Traversal : In postorder traversal , first we traverse the left subtree, then the right subtree and finally the root node. Postorder traversal for the above example is 40 50 20 60 70 30 10.

Algorihtm postorder(Tree):

Recursively traverse left sub-tree.
Recursively traverse right sub-tree.
Visit root node.

Tree Traversals: Inorder Postorder Preorder

BST: Binary Search Tree Program

BST: Search a node in Binary Search Tree

BST: Insertion in a Binary Search Tree

Tree Traversals: Depth First Search (DFS)

C Code for Depth First Search

Run

#include<stdio.h>
#include<stdlib.h>
struct node
{
  int data;
  struct node *left;
  struct node *right;
};

struct node *newNode (int data)
{
  struct node *node = (struct node *) malloc (sizeof (struct node));
  node->data = data;
  node->left = NULL;
  node->right = NULL;

  return (node);
}

/* Given a binary tree, print its nodes in inorder*/
void Inorder (struct node *node)
{
  if (node == NULL)
    return;

  Inorder (node->left);
  printf ("%d ", node->data);
  Inorder (node->right);
}

/* Given a binary tree, print its nodes in preorder*/
void Preorder (struct node *node)
{
  if (node == NULL)
    return;

  printf ("%d ", node->data);
  Inorder (node->left);
  Inorder (node->right);
}

/* Given a binary tree, print its nodes in postorder*/
void Postorder (struct node *node)
{
  if (node == NULL)
    return;

  Inorder (node->left);
  Inorder (node->right);
  printf ("%d ", node->data);
}

/* Driver program to test above functions*/
int main ()
{
  struct node *root = newNode (10);
  root->left = newNode (20);
  root->right = newNode (30);
  root->left->left = newNode (40);
  root->left->right = newNode (50);

  printf ("\nInorder traversal of binary tree is \n");
  Inorder (root);

  printf ("\nPreorder traversal of binary tree is \n");
  Preorder (root);

  printf ("\nPostorder traversal of binary tree is \n");
  Postorder (root);

  getchar ();
  return 0;
}

Output:

Inorder traversal of binary tree is
40 20 50 10 30

Preorder traversal of binary tree is
10 40 20 50 30

Postorder traversal of binary tree is
40 20 50 30 10

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Introduction to Trees

Binary Trees

Binary Tree in Data Structures (Introduction)
Tree Traversals: Inorder Postorder Preorder : C | C++ | Java
Inorder Postorder PreOrder Traversals Examples
- Inorder Tree Traversal in Binary Tree: C | C++ | Java
- Preorder Tree Traversal in Binary Tree : C | C++ | Java
- Postorder Tree Traversal in Binary Tree : C | C++ | Java
Tree Traversal without Recursion
- Postorder Preorder Inorder Traversal without recursion
- Inorder Tree Traversal without Recursion – C | C++ | Java
- Preorder Tree Traversal without Recursion – C | C++ | Java
- Postorder Tree Traversal without Recursion – C | C++ | Java

Binary Search Trees

Binary search tree in Data Structures (Introduction)
- BST: Introduction to Binary Search Tree
- BST: Binary Search Tree Program : C | C++ | Java
- BST: Search a node in Binary Search Tree : C | C++ | Java
- BST: Insertion in a Binary Search Tree : C | C++ | Java
- BST: Deletion in a Binary Search Tree : C | C++ | Java

Traversals

Traversal in Trees
Tree Traversals: Breadth-First Search (BFS) : C | C++ | Java
Tree Traversals: Depth First Search (DFS) : C | C++ | Java
Construct a Binary Tree from Postorder and Inorder

B – Trees

B-Tree
- B-Tree: Introduction
- B-Tree: Insertion : C | C++ | Java
- B-Tree: Deletion : C | C++ | Java

AVL Trees

AVL Trees
- AVL Trees: Introduction
- AVL Tree Insertion : C | C++ | Java
- AVL Tree Deletion : C | C++ | Java
- Insertion in a Binary Tree (Level Order) – C | C++ | Java
- Searching in Binary Tree – C | C++ | Java
- Searching in a Binary Search Tree – C | C++ | Java

Complete Programs for Trees

Depth First Traversals – C | C++ | Java
Level Order Traversal – C | C++ | Java
Construct Tree from given Inorder and Preorder traversals – C | C++ | Java
Construct Tree from given Postorder and Inorder traversals – C | C++ | Java
Construct Tree from given Postorder and Preorder traversal – C | C++ | Java
Find size of the Binary tree – C | C++ | Java
Find the height of binary tree – C | C++ | Java
Find maximum in binary tree – C | C++ | Java
Check whether two tree are identical- C| C++| Java
Spiral Order traversal of Tree- C | C++| Java
Level Order Traversal Line by Line – C | C++| Java
Hand shaking lemma and some Impotant Tree Properties.
Check If binary tree if Foldable or not.- C| C++| Java
check whether tree is Symmetric – C| C++| Java.
Check for Children-Sum in Binary Tree- C|C++| Java
Sum of all nodes in Binary Tree- C | C++ | Java
Lowest Common Ancestor in Binary Tree- C | C++ | Java