PostOrder

package prep_32_binarytrees;

public class PostOrder {
	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;
		}

		/*
		 * Given a binary tree, print its nodes according to the "bottom-up" postorder
		 * traversal.
		 */
		void printPostorder(Node node) {
			if (node == null)
				return;

			// first recur on left subtree
			printPostorder(node.left);

			// then recur on right subtree
			printPostorder(node.right);

			// now deal with the node
			System.out.print(node.key + " ");
		}

		/* Given a binary tree, print its nodes in inorder */
		void printInorder(Node node) {
			if (node == null)
				return;

			/* first recur on left child */
			printInorder(node.left);

			/* then print the data of node */
			System.out.print(node.key + " ");

			/* now recur on right child */
			printInorder(node.right);
		}

		/* Given a binary tree, print its nodes in preorder */
		void printPreorder(Node node) {
			if (node == null)
				return;

			/* first print data of node */
			System.out.print(node.key + " ");

			/* then recur on left sutree */
			printPreorder(node.left);

			/* now recur on right subtree */
			printPreorder(node.right);
		}

		// Wrappers over above recursive functions
		void printPostorder() {
			printPostorder(root);
		}

		void printInorder() {
			printInorder(root);
		}

		void printPreorder() {
			printPreorder(root);
		}
	}
}