print left view of a binary tree

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

class Node{
  public:
      int data;
      Node *left,*right;
      Node(int key){
        data=key;
        left=NULL;
        right=NULL;
        }
  };

void PrintLeftView(Node *root){
if(root==NULL)
  return ;
queue<Node*>q;
q.push(root);
q.push(NULL);
cout<<" "<<root->data;
while(!q.empty()){
  Node *temp=q.front();
  q.pop();
  if(temp!=NULL){
    if(temp->left!=NULL)
        q.push(temp->left);
    if(temp->right!=NULL)
        q.push(temp->right);
    }
  else
    if(q.size()>0){
        q.push(NULL);
        temp=q.front();
        cout<<" "<<temp->data;
        }
    }
}

int main(){
  Node *root=NULL;
  Node *newnode=new Node(1);
  root=newnode;
  root->left=new Node(2);
  root->right=new Node(3);
  (root->left)->left=new Node(4);
  (root->right)->right=new Node(5);
  ((root->left)->left)->left=new Node(6);
  PrintLeftView(root);
  return 0;
  }