AVL Tree in c++

/* This program demonstrate AVL Tree implementation
 * with Double Rotation Right(DRR), Double rotation left(DRL),
 * Single rotation Left(SRL), Single Rotation Right(SRR) and
 * insert rotines.
 */


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

template<class T>
class AVL{
private:
  T data;
  AVL *left;
  AVL *right;
  int balance;

public:
  AVL(T d = 0, int b = 0, AVL<T> *l = NULL, AVL<T> *r = NULL):data(d), balance(b),left(l),right(r){};
  AVL<T> *insert(T val);
  void preorder();
  void level_order_traversal( AVL<T>* rootNode);
  bool search(T val);
  AVL<T>* DRR();
  AVL<T>* DRL();
  AVL<T>* SRR();
  AVL<T>* SRL();
  int Balance(AVL<T>* r); 
};

template<class T>
AVL<T>* AVL<T> :: DRR()
{
  right = right -> SRL();
  return SRR();
}


template<class T>
AVL<T>* AVL<T> :: DRL()
{
  left = left -> SRR();
  return SRL();

}

template<class T>
AVL<T>* AVL<T> :: SRR()
{
  AVL<T> *Temp;
  Temp = right;
  right = Temp-> left;
  Temp -> left = this;
  balance = max(Balance(left),Balance(right))+1;
  Temp -> balance = max(Balance(Temp -> left),Balance(Temp -> right))+1;
  return Temp;
}

template<class T>
AVL<T>* AVL<T> :: SRL()
{
  AVL<T> *Temp;
  Temp = left;
  left = Temp -> right;
  Temp -> right = this;
  balance = max(Balance(left),Balance(right))+1;
  Temp -> balance = max(Balance(Temp -> left),Balance(Temp -> right))+1;

  return Temp;
}

template<class T>
int AVL<T> :: Balance(AVL<T> *r)
{
  if(r == NULL)
    return -1;
  else
    return(r -> balance);
}

template<class T>
AVL<T>* AVL<T>:: insert(T val)
{
  AVL<T> * Temp = this;
  if(val < data && left == NULL){
    left = new AVL<T>(val);
  }else if(val > data && right == NULL){
    right = new AVL<T>(val);
  }else if(val < data){
    left = left ->insert(val);
    if(Balance(left) -  Balance(right) == 2)
      if(val < left->data)
    Temp = SRL();
      else 
    Temp = DRL();
  }else if(val > data){
    right = right ->insert(val);
    if(Balance(right) - Balance(left) == 2)
      if(val > right->data)
    Temp = SRR();
      else
    Temp = DRR();
  }else{
    cout <<"Duplicate value";
  }
  Temp->balance = max(Balance(Temp ->left),Balance(Temp->right))+1;
  return Temp;
}

template<class T>
void AVL<T> :: preorder()
{
  cout<<data<<"\t"; 
  if(left != NULL)
    left->preorder();
  if(right != NULL)
    right->preorder();
}

template<class T>
bool AVL<T>:: search(T val)
{
  bool re;
  if(data == val )
   re =  true;
  else if(val < data && left != NULL){
    re = left ->  search(val);
  }else if (val > data && right != NULL){
    re = right -> search(val);
  }
    return re;
  
}

template<class T> 
void AVL<T> :: level_order_traversal( AVL<T>* root)
{
  queue<AVL<T>*> Queue;
  AVL<T>* Traverse; 
  int count = 0,m = 1,x = 1; 
    Queue.push(root);
    while(!Queue.empty()){
      Traverse = Queue.front();
      Queue.pop();
      cout<<Traverse->data<<"\t";
      count++;
      if(count == m){
    cout<<"\n";
    m = x * 2 + count;
    x= x * 2;
      }
      if(Traverse->left != NULL) 
    Queue.push(Traverse->left);
      if(Traverse->right != NULL)
    Queue.push(Traverse->right); 
    }  
}



int main()
{
  AVL<int> *root = NULL;
  int choice;
  while(1){
    cout<<"\n 1.Insert.";
    cout<<"\n 2.Search";
    cout<<"\n 3.Print";
    cout<<"\n 4.Exit";
    cout<<"\n Enter your choice:";
    cin>>choice;
    switch(choice){

    case 1:
      int val;
      cout<<"\n Enter the value to insert:";
      cin>>val;
      if(root == NULL){
    root = new AVL<int>(val);
      }else{
    root = root -> insert(val);
      }
      break;

    case 2:
      cout<<"\n Enter the value to search:";
      cin>>val;
      if(root == NULL){
    cout<<"\n Empty tree.";
      }else if(root->search(val) == true){
    cout<<"\n The data "<<val <<" present in the Tree";
      }else{
    cout<<"\n The data "<<val <<" not present in the Tree";
      }
      break;
      
    case 3:
      if(root == NULL){
    cout<<"\n Empty Tree.";
      }else{
    cout<<"\n--------In Preorder Traversal---------\n";
    root->preorder();
    cout<<"\n--------In Level order Travelsal------\n";
    root->level_order_traversal(root);
      }
      break;

    case 4:
      exit(0);
      break;

    default:
      cout<<"Enter correct choice";
    }
  }
}