Inorder Traversal: Visit the left subtree, root, and then the right subtree.

Preorder Traversal: Visit the root, left subtree, and then the right subtree.

Postorder Traversal: Visit the left subtree, right subtree, and then the root.

void inorder(Node* root) {
    if (!root) return;
    inorder(root->left);
    cout << root->key << " ";
    inorder(root->right);
}