Binary Tree creation in CPP

Binary_Tree.cpp

#include <iostream>
#include <queue>
using namespace std;

struct Node {
    int data;
    struct Node * left;
    struct Node * right;
}*root=NULL;

int main(){
    queue<Node*> q;
    int left,right,ele;
    struct Node *node, *temp;
    cout << "Enter root data : ";
    cin >> ele;
    if(ele != -1){
        root = new Node;
        root -> data = ele;
        root -> left = NULL;
        root -> right = NULL;
        q.push(root);
    }
    while(!q.empty()){
        node = q.front();
        q.pop();
        cout << "Enter left child of " << node->data << ": ";
        cin>>left;
        if(left!=-1){
            temp = new Node;
            temp->data = left;
            temp->left = NULL;
            temp->right = NULL;
            node -> left = temp;
            q.push(temp);
        }
        cout << "Enter right child of " << node->data << ": ";
        cin>>right;
        if(right!=-1){
            temp = new Node;
            temp->data = right;
            temp->left = NULL;
            temp->right = NULL;
            node -> right = temp;
            q.push(temp);
        }
    }
    
    // Any Tree Traversal methods can be called..
}