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In this example, we will learn how to perform preorder tree traversal in a Java program.
class Node { int item; Node left, right; public Node(int key) { item = key; left = right = null; } } class Tree { //The root of Tree Node root; Tree() { root = null; } void preorder(Node node) { if (node == null) return; //Traverse the root node System.out.print(node.item + -> //Traverse the left child elements preorder(node.left); //Traverse Right Sub-element preorder(node.right); } public static void main(String[] args) { //Creating Tree Object Tree tree = new Tree(); //Creating Tree Nodes tree.root = new Node(1); tree.root.left = new Node(12); tree.root.right = new Node(9); tree.root.left.left = new Node(5); tree.root.left.right = new Node(6); //Preorder Tree Traversal System.out.println("\nPreorder Tree Traversal \t"); tree.preorder(tree.root); } }
Output Result
Preorder Tree Traversal 1->12->5->6->9->
In the above example, we have implemented the tree data structure in Java. Here, we are performing the preorder traversal of the tree.