Mirror of a Binary Tree in C++

By Zeeshan Alam

In this tutorial, we will learn about how to build a mirror of the binary tree in C++.

We will also see examples to understand the concept in a better way.

Find or Create  the Mirror of a Binary tree in C++

Mirror of the binary tree is a tree in which all the left and right children of non-leaf nodes are interchanged.

Let’s see the example,

                       1                      1
                     /  \                    / \
                    2    3     --->         3   2
                  /  \  / \               /  \ /  \
                 4   5 6   7             7   6 5   4

So, In the above example, we can understand the mirror of the binary tree in which left and right children of non-leaf node are interchanged.

We will use the recursive approach to find the mirror of the binary tree.

pseudocode for the recursive approach

Let’s see the pseudocode for the recursive approach to convert into mirror tree,

mirror(Node* root) 
   if(root==NULL) then do 
      return;
   mirror(root->left);
   mirror(root->right);
   Node* temp=root->left;
   root->left=root->right;
   root->right=temp; 

So, we can easily understand the recursive approach in above pseudocode.

Code implementation in C++: Mirror of a binary tree

#include<iostream>
#include<bits/stdc++.h>
using namespace std;
struct Node{
  int data;
  Node* left;
  Node* right;
};
Node* create(int x){
  Node* temp=new Node;
  temp->data=x;
  temp->left=NULL;
  temp->right=NULL;
  return temp;
}
//function to find inorder traversal
void inorder(Node* root){
  if(root==NULL)return;
  inorder(root->left);
  cout<<root->data<<" ";
  inorder(root->right);
}
//funtion to convert into mirror tree
void mirror(Node* root) 
{
    if(root==NULL)return;
    mirror(root->left);
    mirror(root->right);
    Node* temp=root->left;
    root->left=root->right;
    root->right=temp;  
}
//main fuction
int main(){
  Node* root=create(1);
  root->left=create(2);
  root->left->right=create(5);
  root->left->left=create(4);
  root->right=create(3);
  root->right->left=create(6);
  root->right->right=create(7);
    mirror(root);
    cout<<"inorder traversal of the mirror of the binary tree is :"<<" ";
    inorder(root);
    return 0;
}

Output

inorder traversal of the mirror of the binary tree is : 7 3 6 1 5 2 4

You may also learn,

Right view of the binary tree in C++

Top view of binary tree in C++

Bottom view of the binary tree in C++