Inorder Traversal of binary tree in Java

1. Traverse the left subtree by recursively calling the in-order function.

2. Display the data part of the root (or current node).

3. Traverse the right subtree by recursively calling the in-order function.

class Node {

      int key;

      Node left, right;

      public Node(int item) {

            key = item;

            left = right = null;

      }

}

class BinaryTree {

      /** Root of Binary Tree*/

      Node root;

      BinaryTree() {

            root = null;

      }

      /** Inorder binary tree traversal. */

      void printInorder(Node node) {

            if(node==null) {

                  return;

            }

            printInorder(node.left);

            System.out.println(node.key);

            printInorder(node.right);

      }

      /** Call InPrder traversal. */

      void printInorder() {

            printInorder(root);

      }

}

public class InorderTraversal {

      public static void main(String[] args) {

            BinaryTree bTree = new BinaryTree();

            bTree.root = new Node(1);

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

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

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

            bTree.root.left.right = new Node(5);

            bTree.root.left.left.left = new Node(6);

            bTree.root.left.left.right = new Node(7);

            System.out.println("\nInorder traversal of binary tree is ");

            bTree.printInorder();

      }

}