traversal_binary_tree.cpp

//preorder, inorder, postorder traversal in binary tree in cpp

#include <iostream> 
using namespace std; 

/* A binary tree node has data, pointer to left child 
and a pointer to right child */
struct Node 
{ 
	int data; 
	struct Node* left, *right; 
	Node(int data) 
	{ 
		this->data = data; 
		left = right = NULL; 
	} 
}; 

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

	printPostorder(node->left); 

	printPostorder(node->right); 

	cout << node->data << " "; 
} 

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

	printInorder(node->left); 

	cout << node->data << " "; 

	printInorder(node->right); 
} 

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

	cout << node->data << " "; 
	printPreorder(node->left); 

	printPreorder(node->right); 
} 

/* Driver program to test above functions*/
int main() 
{ 
	struct Node *root = new Node(1); 
	root->left			 = new Node(2); 
	root->right		 = new Node(3); 
	root->left->left	 = new Node(4); 
	root->left->right = new Node(5); 

	cout << "\nPreorder traversal of binary tree is \n"; 
	printPreorder(root); 

	cout << "\nInorder traversal of binary tree is \n"; 
	printInorder(root); 

	cout << "\nPostorder traversal of binary tree is \n"; 
	printPostorder(root); 

	return 0; 
}