tree in ds code example

Example 1: binary tree in ds

# Python program to for tree traversals 

# A class that represents an individual node in a 
# Binary Tree 
class Node: 
	def __init__(self,key): 
		self.left = None
		self.right = None
		self.val = key 


# A function to do inorder tree traversal 
def printInorder(root): 

	if root: 

		# First recur on left child 
		printInorder(root.left) 

		# then print the data of node 
		print(root.val), 

		# now recur on right child 
		printInorder(root.right) 



# A function to do postorder tree traversal 
def printPostorder(root): 

	if root: 

		# First recur on left child 
		printPostorder(root.left) 

		# the recur on right child 
		printPostorder(root.right) 

		# now print the data of node 
		print(root.val), 


# A function to do preorder tree traversal 
def printPreorder(root): 

	if root: 

		# First print the data of node 
		print(root.val), 

		# Then recur on left child 
		printPreorder(root.left) 

		# Finally recur on right child 
		printPreorder(root.right) 


# Driver code 
root = Node(1) 
root.left	 = Node(2) 
root.right	 = Node(3) 
root.left.left = Node(4) 
root.left.right = Node(5) 
print "Preorder traversal of binary tree is"
printPreorder(root) 

print "\nInorder traversal of binary tree is"
printInorder(root) 

print "\nPostorder traversal of binary tree is"
printPostorder(root)

Example 2: tree data structure

If root is NULL 
   then create root node
return

If root exists then
   compare the data with node.data
   
   while until insertion position is located

      If data is greater than node.data
         goto right subtree
      else
         goto left subtree

   endwhile 
   
   insert data
	
end If

Example 3: tree ds

// Tree traversal in C

#include <stdio.h>
#include <stdlib.h>

struct node {
  int item;
  struct node* left;
  struct node* right;
};

// Inorder traversal
void inorderTraversal(struct node* root) {
  if (root == NULL) return;
  inorderTraversal(root->left);
  printf("%d ->", root->item);
  inorderTraversal(root->right);
}

// preorderTraversal traversal
void preorderTraversal(struct node* root) {
  if (root == NULL) return;
  printf("%d ->", root->item);
  preorderTraversal(root->left);
  preorderTraversal(root->right);
}

// postorderTraversal traversal
void postorderTraversal(struct node* root) {
  if (root == NULL) return;
  postorderTraversal(root->left);
  postorderTraversal(root->right);
  printf("%d ->", root->item);
}

// Create a new Node
struct node* createNode(value) {
  struct node* newNode = malloc(sizeof(struct node));
  newNode->item = value;
  newNode->left = NULL;
  newNode->right = NULL;

  return newNode;
}

// Insert on the left of the node
struct node* insertLeft(struct node* root, int value) {
  root->left = createNode(value);
  return root->left;
}

// Insert on the right of the node
struct node* insertRight(struct node* root, int value) {
  root->right = createNode(value);
  return root->right;
}

int main() {
  struct node* root = createNode(1);
  insertLeft(root, 12);
  insertRight(root, 9);

  insertLeft(root->left, 5);
  insertRight(root->left, 6);

  printf("Inorder traversal \n");
  inorderTraversal(root);

  printf("\nPreorder traversal \n");
  preorderTraversal(root);

  printf("\nPostorder traversal \n");
  postorderTraversal(root);
}