Print mirror of a binary tree.

Question

consider a tree:

Then print it's mirror, in this case it would be: 30 40 20 25 15 45 37

Answer 1

I have used Level Order traversal to do so (level order is implemented by queue in function mirrorPrint()), point to be noted here is that my tree will take input as long as input is not 0 which is correct in this case, otherwise you can change the tree according to your need.

#include<iostream>
#include<stdlib.h>
#include<queue>
using namespace std;

struct node{
    int value;
    struct node *left;
    struct node *right;
};

struct node *root=NULL;
int count=1;

struct node *createBtree(struct node *p,int nodeValue){
    if(p==NULL){
        p=(struct node *)malloc(sizeof(struct node));
        p->right=p->left=NULL;
        p->value=nodeValue;
        count++;
    }
    else{
        if(count%2==0)
            p->left=createBtree(p->left,nodeValue);
        else
            p->right=createBtree(p->right,nodeValue);

    }
    return p;
}

void mirrorPrint(struct node *p){
    struct node *tmp;
    if(root==NULL)
        return;
    queue <struct node *> myQueue;
    myQueue.push(root);
    while(!myQueue.empty()){
       tmp=myQueue.front();
       cout << tmp->value << ' ';
       myQueue.pop();
       if(tmp->right!=NULL)
         myQueue.push(tmp->right);
      if(tmp->left!=NULL)
       myQueue.push(tmp->left);
    }
}
int main(){
    int nodeValue;
    cin >> nodeValue;
    while(nodeValue){
        root=createBtree(root,nodeValue);
        cin >> nodeValue;
    }
    mirrorPrint(root);

}