Insert into BST

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
        TreeNode* insertIntoBST(TreeNode* root, int val) {
 if(root==NULL){
     return new TreeNode(val);
 }
 TreeNode*curr=root;
 while(root!=NULL){
     if(val>curr->val){
         if(curr->right!=NULL){
             curr=curr->right;
         }
         else{
             curr->right=new TreeNode(val);
             break;
         }
     }
     if(val<curr->val){
         if(curr->left!=NULL){
             curr=curr->left;
         }else{
             curr->left=new TreeNode(val);
             break;
         }
     }
 }
 return root;
 }
};