What factors could cause bad_alloc? - c++

Question

I was writing an AVL tree implementation but got an error due to bad_alloc on another platform. However, the code works perfectly for me in CS50 IDE without any warning.
In my code, I used new keyword to declare objects and I did deleted them after using.
My question is that what other factors could result in this bad_alloc error? And how can I solve it?
#include <vector>
using namespace std;
class node {
public:
int value;
int height;
node* left;
node* right;
node();
};
// freeing the dynamically allocated memory
void freeTree(node* root){
if((root->left) != nullptr){
freeTree(root->left);
}
if((root->right) != nullptr){
freeTree(root->right);
}
delete root;
}
node::node(){
height = 1;
}
int get_height(node* n){
if(n == NULL){
return 0;
}
return n->height;
}
int get_balance_factor(node* n){
if(n == NULL){
return 0;
}
if(n->value == 0){
return 0;
}
return (get_height(n->left))-(get_height(n->right));
}
// prints out the AVL tree by inorder traversal
void inorder(node* root){
if((root->left) != nullptr){
inorder(root->left);
}
cout << root->value << ' ';
if((root->right) != nullptr){
inorder(root->right);
}
}
// prints out the AVL tree by preorder traversal
void preorder(node* root){
cout << root->value << ' ';
if((root->left) != nullptr){
preorder(root->left);
}
if((root->right) != nullptr){
preorder(root->right);
}
}
// prints out the AVL tree by postorder traversal
void postorder(node* root){
if((root->left) != nullptr){
postorder(root->left);
}
if((root->right) != nullptr){
postorder(root->right);
}
cout << root->value << ' ';
}
node* left_rotation(node* root){
node* temp = root->right;
root->right = root->right->left;
temp->left = root;
root->height = max(get_height(root->left),get_height(root->right))+1;
temp->height = max(get_height(temp->left),get_height(temp->right))+1;
return temp;
}
node* right_rotation(node* root){
node* temp = root->left;
root->left = root->left->right;
temp->right = root;
root->height = max(get_height(root->left),get_height(root->right))+1;
temp->height = max(get_height(temp->left),get_height(temp->right))+1;
return temp;
}
node* add_node(int k, node* root){
// cout << "inserting " << k << endl;
// BST insertion
if(root == NULL){
node* temp = new node();
temp->value = k;
return temp;
}
if(root->value == 0){
node* temp = new node();
temp->value = k;
return temp;
}
else if(k > (root->value)){
root->right = add_node(k, root->right);
}
else if(k < (root->value)){
root->left = add_node(k, root->left);
}
else{
return root;
}
root->height = max(get_height(root->left),get_height(root->right))+1;
// rebalancing
int bf = get_balance_factor(root);
// right-heavy tree
if(bf < -1){
return left_rotation(root);
}
// left-heave tree
if(bf > 1){
return right_rotation(root);
}
return root;
}
int main(){
// initializing an avl tree
node* root = new node();
// handling input
vector<string> input;
while(true){
string temp;
cin >> temp;
input.push_back(temp);
if(cin.peek() == 32){
cin.ignore();
}
else if(cin.peek() == 10){
break;
}
}
// processing input
for(int i = 0; i < (int)input.size()-1; i++){
string temp = input[i];
char operation = temp[0];
int number = stoi(temp.substr(1, temp.length()-1));
if(operation == 'A'){
root = add_node(number, root);
}
else if(operation == 'D'){
// call delete node function
}
}
// traversal
string traversal = input[input.size()-1];
if(traversal == "PRE"){
preorder(root);
}
else if(traversal == "IN"){
inorder(root);
}
else if(traversal == "POST"){
postorder(root);
}
freeTree(root);
return 0;
}```