// Binary Tree in Java

// Node creation

class Node {

int key;

Node left, right;

public Node(int item) {

key = item;

left = right = null;

}

}

class BinaryTree {

Node root;

BinaryTree(int key) {

root = new Node(key);

}

BinaryTree() {

root = null;

}

// Traverse Inorder

public void traverseInOrder(Node node) {

if (node != null) {

traverseInOrder(node.left);

System.out.print(" " + node.key);

traverseInOrder(node.right);

}

}

// Traverse Postorder

public void traversePostOrder(Node node) {

if (node != null) {

traversePostOrder(node.left);

traversePostOrder(node.right);

System.out.print(" " + node.key);

}

}

// Traverse Preorder

public void traversePreOrder(Node node) {

if (node != null) {

System.out.print(" " + node.key);

traversePreOrder(node.left);

traversePreOrder(node.right);

}

}

public static void main(String[] args) {

BinaryTree tree = new BinaryTree();

tree.root = new Node(1);

tree.root.left = new Node(2);

tree.root.right = new Node(3);

tree.root.left.left = new Node(4);

System.out.print("Pre order Traversal: ");

tree.traversePreOrder(tree.root);

System.out.print("\nIn order Traversal: ");

tree.traverseInOrder(tree.root);

System.out.print("\nPost order Traversal: ");

tree.traversePostOrder(tree.root);

}

}