Modify this code and add a function in the program called Display_less. Function should ask user to enter a number then display all elements from the tree that are less than or equal to the number. Note that the number may not be present in the tree.

#include

using namespace std;

/* To represent a node of Binary Search Tree*/

struct node{

int value;

struct node *left, *right;

node(int value){

this->value = value; // To initialize the node's value of BST with given value

this->left = this->right = NULL; // To initialize left and right pointers of this node as NULL

}

};

/* createBST() to insert value in a Binary Search Tree*/

struct node * createBST(struct node *root, int value){

if (root == NULL){ // If root is NULL

return new node(value); // Create a new node and return this node

}

if (value < root->value) // if given value is less than root's value then Go left in BST

root->left = createBST(root->left, value);

else // if given value is more than root's value then Go right in BST

root->right = createBST(root->right, value);

return root; // Returns the root

}

// To display the elements of the tree in In-order form

void inorder(struct node *root){

if(root != NULL){

inorder(root->left);

cout << root->value << " ";

inorder(root->right);

}

}

// To display the elements of the tree in Post-order form

void postorder(struct node *root){

if(root != NULL){

postorder(root->left);

postorder(root->right);

cout << root->value << " ";

}

}

// To display the elements of the tree in Pre-order form

void preorder(struct node *root){

if(root != NULL){

cout << root->value << " ";

preorder(root->left);

preorder(root->right);

}

}

/* Recursive Search function which will find a particular number entered by user */

void search(struct node *root, int number){

if(root == NULL){ // Base-Case 1 : If the given number is not found in BST

cout << "Given number : " << number << " is not found in Binary Search Tree! " << endl;

return; // return

}

if(root->value == number){ // Base-Case 2 : If we found the number in BST

cout << "Given number : " << number << " is found in Binary Search Tree! " << endl;

return; // return

}

if (number < root->value) // If given number is less than root's value then search in left subtree

search(root->left, number);

else // If given number is more than root's value then search in right subtree

search(root->right, number);

}

int main(){

struct node *root = NULL; // Create a root for Binary Search Tree

int value = 0, number;

while(1){ // Run an infinite loop, it will stop when a user enters any negative number

cout << "Please enter the number in BST: ";

cin >> value;

if(value < 0){ // When a user enters any negative number, just break the infinite loop

break;

}

root = createBST(root, value); // Call createBST to insert the given value in BST

}

cout << "Displaying the elements of the tree in In-order, Post-order and Pre-order form : " << endl;

cout << "IN-ORDER FORM: " << endl;

inorder(root);

cout << " POST-ORDER FORM: " << endl;

postorder(root);

cout << " Please enter a number to be searched in the Binary Search Tree: " << endl;

cin >> number;

search(root, number); // Search the given number in BST

}

Data structures in C++