C++ Program to Perform Preorder Non-Recursive Traversal of a Given Binary Tree Full Project For Beginners

  • Post author:
  • Post category:c++
  • Post comments:0 Comments

 

 

main.cpp

 

 

#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <stack>
 
using namespace std;
 
/* A binary tree node has data, left child and right child */
struct node
{
        int data;
        struct node* left;
        struct node* right;
};
 
/* Helper function that allocates a new node with the given data and
 NULL left and right  pointers.*/
struct node* newNode(int data)
{
    struct node* node = new struct node;
    node->data = data;
    node->left = NULL;
    node->right = NULL;
    return (node);
}
 
// An iterative process to print preorder traversal of Binary tree
void iterativePreorder(node *root)
{
    // Base Case
    if (root == NULL)
        return;
 
    // Create an empty stack and push root to it
    stack<node *> nodeStack;
    nodeStack.push(root);
 
    /* Pop all items one by one. Do following for every popped item
     a) print it
     b) push its right child
     c) push its left child
     Note that right child is pushed first so that left is processed first */
    while (nodeStack.empty() == false)
    {
        // Pop the top item from stack and print it
        struct node *node = nodeStack.top();
        printf("%d ", node->data);
        nodeStack.pop();
 
        // Push right and left children of the popped node to stack
        if (node->right)
            nodeStack.push(node->right);
        if (node->left)
            nodeStack.push(node->left);
    }
}
 
int main()
{
    /* Constructed binary tree is
           10
         /   \
        8      2
      /  \    /
     3     5  2
     */
    struct node *root = newNode(10);
    root->left = newNode(8);
    root->right = newNode(2);
    root->left->left = newNode(3);
    root->left->right = newNode(5);
    root->right->left = newNode(2);
    cout<<"Pre order traversal: ";
    iterativePreorder(root);
    return 0;
}

Leave a Reply