How to determine if a binary tree is height-balanced (2)

#include<cstdlib>
#include<iostream>
using namespace std;
class Node{
  public:
      int data;
      Node *left,*right;
      Node(int key){
        data=key;
        left=right=NULL;
        }
  };

int IsBalanced(Node *root,int &height){
 int lh=0,rh=0;
 if(root==NULL){
    height=0;
    return 1;
    }
 int l=IsBalanced(root->left,lh);
 int r=IsBalanced(root->right,rh);
 height=max(lh,rh)+1;
 if(abs(lh-rh)>=2)
   return 0;
 return l && r;
 }

void Insert(Node **root_ref,int key){
  if(*root_ref==NULL){
    *root_ref=new Node(key);
    return;
    }
  if((*root_ref)->data<key)
    Insert(&((*root_ref)->right),key);
  else
     if((*root_ref)->data>key)
       Insert(&((*root_ref)->left),key);
  }

int main(){
 Node *root=NULL;
 Insert(&root,5);
 Insert(&root,7);
 Insert(&root,6);
 Insert(&root,2);
 Insert(&root,8);
 int height=0;
 if(IsBalanced(root,height))
   cout<<"yes";
 else
   cout<<"no";
 }