Deleting a node in 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 DeleteDeepest( Node* root,Node* d_node){
  queue<Node*> q;
  q.push(root);
  Node* temp;
  while (!q.empty()) {
    temp = q.front();
    q.pop();
    if (temp->right) {
      if (temp->right == d_node) {
        temp->right = NULL;
        delete d_node;
        return;
        }
      else
        q.push(temp->right);
      }
    if (temp->left) {
      if (temp->left == d_node) {
        temp->left = NULL;
        delete d_node;
        return;
        }
      else
        q.push(temp->left);
      }
    }
  }

void Delete( Node** root_ref, int key){
 if (*root_ref == NULL)
    return ;
 if ((*root_ref)->left == NULL && (*root_ref)->right== NULL) {
    if ((*root_ref)->data== key)
        *root_ref== NULL;
    return ;
    }
 queue<Node*> q;
 q.push(*root_ref);
 Node* temp;
 Node* key_node = NULL;
 while (!q.empty()) {
    temp = q.front();
    q.pop();
    if (temp->data== key)
        key_node = temp;
    if (temp->left)
        q.push(temp->left);
    if (temp->right)
        q.push(temp->right);
    }
 if (key_node != NULL) {
    int x = temp->data;
    DeleteDeepest(*root_ref,temp);
    if(key_node!=temp)
    key_node->data = x;
    }
 }

void preorder(Node *root){
  if(root==NULL)
     return;
  cout<<" "<<root->data;
  preorder(root->left);
  preorder(root->right);
  }

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);
  cout<<"preorder traversing : ";
  preorder(root);
  Delete(&root,1);
  cout<<endl<<"after deletion of 2 from tree :";
  preorder(root);
  return 0;
  }