// Tree traversal in C++

​

#include <iostream>

using namespace std;

​

struct Node {

  int data;

  struct Node *left, *right;

  Node(int data) {

    this->data = data;

    left = right = NULL;

  }

};

​

// Preorder traversal

void preorderTraversal(struct Node* node) {

  if (node == NULL)

    return;

​

  cout << node->data << "->";

  preorderTraversal(node->left);

  preorderTraversal(node->right);

}

​

// Postorder traversal

void postorderTraversal(struct Node* node) {

  if (node == NULL)

    return;

​

  postorderTraversal(node->left);

  postorderTraversal(node->right);

  cout << node->data << "->";

}

​

// Inorder traversal

void inorderTraversal(struct Node* node) {

  if (node == NULL)

    return;

​

  inorderTraversal(node->left);

  cout << node->data << "->";

  inorderTraversal(node->right);

}

​

int main() {

  struct Node* root = new Node(1);

  root->left = new Node(12);

  root->right = new Node(9);

  root->left->left = new Node(5);

  root->left->right = new Node(6);

​

  cout << "Inorder traversal ";

  inorderTraversal(root);

​

  cout << "\nPreorder traversal ";

  preorderTraversal(root);

​

  cout << "\nPostorder traversal ";

  postorderTraversal(root);

#include <bits/stdc++.h>

​

using namespace std;

​

struct node {

  int data;

  struct node * left, * right;

};

​

vector < int > preOrderTrav(node * curr) {

  vector < int > preOrder;

  if (curr == NULL)

    return preOrder;

​

  stack < node * > s;

  s.push(curr);

​

  while (!s.empty()) {

    node * topNode = s.top();

    preOrder.push_back(topNode -> data);

    s.pop();

    if (topNode -> right != NULL)

      s.push(topNode -> right);

    if (topNode -> left != NULL)

      s.push(topNode -> left);

  }

  return preOrder;

​

}

​

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);

}

​

int main() {

​

  struct node * root = newNode(1);

  root -> left = newNode(2);

  root -> right = newNode(3);

  root -> left -> left = newNode(4);

  root -> left -> right = newNode(5);

  root -> left -> right -> left = newNode(8);

  root -> right -> left = newNode(6);

  root -> right -> right = newNode(7);

  root -> right -> right -> left = newNode(9);

  root -> right -> right -> right = newNode(10);

​

  vector < int > preOrder;

  preOrder = preOrderTrav(root);

​

  cout << "The preOrder Traversal is : ";

  for (int i = 0; i < preOrder.size(); i++) {

    cout << preOrder[i] << " ";

  }

  return 0;

}

a

s

d

​