finds size of binary tree

Author: NirmalSilwal

CodingBlocks Training/Day20/sizeOfBinaryTree.java

@@ -0,0 +1,112 @@
+package Lecture20;
+
+import java.util.Scanner;
+
+public class sizeOfBinaryTree {
+
+	private class Node {
+		int data;
+		Node left;
+		Node right;
+
+		Node(int data, Node left, Node right) {
+			this.data = data;
+			this.left = left;
+			this.right = right;
+		}
+	}
+
+	private Node root;
+	private int size = 0;
+
+	public sizeOfBinaryTree() {
+		Scanner sc = new Scanner(System.in);
+		this.root = takeTreeInput(sc, null, false);
+	}
+
+	private Node takeTreeInput(Scanner sc, Node parent, boolean isLeftorRight) {
+		if (parent == null) {
+			System.out.print("Enter data for root node: ");
+		} else {
+			if (isLeftorRight) {
+				System.out.print("Enter data for left child of " + parent.data + ": ");
+			} else {
+				System.out.print("Enter data for right child of: " + parent.data + ": ");
+
+			}
+		}
+
+		int data = sc.nextInt();
+		Node node = new Node(data, null, null);
+		this.size++;
+
+		boolean choice = false;
+		System.out.print("Do you have left child for " + node.data + " -> true/false: ");
+		choice = sc.nextBoolean();
+		if (choice) {
+			node.left = this.takeTreeInput(sc, node, true);
+		}
+
+		choice = false;
+		System.out.print("Do you have right child for " + node.data + " -> true/false: ");
+		choice = sc.nextBoolean();
+		if (choice) {
+			node.right = this.takeTreeInput(sc, node, false);
+		}
+
+		return node;
+	}
+
+	public int size() {
+		return this.size(this.root);
+	}
+	
+	private int size(Node node) {
+		if (node == null){
+			return 0;
+		}
+		int lsize = size(node.left);
+		int rsize = size(node.right);
+		
+		int ans = lsize + rsize + 1;
+		
+		return ans;
+	}
+	
+	public static void main(String[] args) {
+
+		sizeOfBinaryTree tree = new sizeOfBinaryTree();
+
+		int treeSize = tree.size();
+		System.out.println("=============\n");
+		System.out.println("size of tree is: " + treeSize);
+	}
+}
+
+
+
+
+/* output: 
+Enter data for root node: 20
+Do you have left child for 20 -> true/false: true
+Enter data for left child of 20: 10
+Do you have left child for 10 -> true/false: true
+Enter data for left child of 10: 28
+Do you have left child for 28 -> true/false: false
+Do you have right child for 28 -> true/false: false
+Do you have right child for 10 -> true/false: true
+Enter data for right child of: 10: 16
+Do you have left child for 16 -> true/false: false
+Do you have right child for 16 -> true/false: false
+Do you have right child for 20 -> true/false: true
+Enter data for right child of: 20: 30
+Do you have left child for 30 -> true/false: 
+true
+Enter data for left child of 30: 42
+Do you have left child for 42 -> true/false: false
+Do you have right child for 42 -> true/false: false
+Do you have right child for 30 -> true/false: false
+=============
+
+size of tree is: 6
+*/