Level Order Traversal

level_order_traversal.cpp

@@ -0,0 +1,88 @@
+// Recursive CPP program for level
+// order traversal of Binary Tree
+#include <bits/stdc++.h>
+using namespace std;
+
+/* A binary tree node has data,
+pointer to left child
+and a pointer to right child */
+class node {
+public:
+	int data;
+	node *left, *right;
+};
+
+/* Function prototypes */
+void printCurrentLevel(node* root, int level);
+int height(node* node);
+node* newNode(int data);
+
+/* Function to print level
+order traversal a tree*/
+void printLevelOrder(node* root)
+{
+	int h = height(root);
+	int i;
+	for (i = 1; i <= h; i++)
+		printCurrentLevel(root, i);
+}
+
+/* Print nodes at a current level */
+void printCurrentLevel(node* root, int level)
+{
+	if (root == NULL)
+		return;
+	if (level == 1)
+		cout << root->data << " ";
+	else if (level > 1) {
+		printCurrentLevel(root->left, level - 1);
+		printCurrentLevel(root->right, level - 1);
+	}
+}
+
+int height(node* node)
+{
+	if (node == NULL)
+		return 0;
+	else {
+		/* compute the height of each subtree */
+		int lheight = height(node->left);
+		int rheight = height(node->right);
+
+		/* use the larger one */
+		if (lheight > rheight) {
+			return (lheight + 1);
+		}
+		else {
+			return (rheight + 1);
+		}
+	}
+}
+
+/* Helper function that allocates
+a new node with the given data and
+NULL left and right pointers. */
+node* newNode(int data)
+{
+	node* Node = new node();
+	Node->data = data;
+	Node->left = NULL;
+	Node->right = NULL;
+
+	return (Node);
+}
+
+int main(void)
+{
+	node* root = newNode(1);
+	root->left = newNode(2);
+	root->right = newNode(3);
+	root->left->left = newNode(4);
+	root->left->right = newNode(5);
+
+	cout << "Level Order traversal of binary tree is \n";
+	printLevelOrder(root);
+
+	return 0;
+}
+