Segregate even and odd nodes in a Linked List GeeksForGeeks Linkedlist Medium

#include<bits/stdc++.h>
using namespace std;

class Node{
    public:
    int data;
    Node *next;
    
    Node(int key){
        this-> data = key;
        next = NULL;
    }
};

void oddaftereven(Node** head){
    Node* odd = NULL;
    Node* even = NULL;
    Node* o = NULL;
    Node* e = NULL;
    Node* curr = *head;
    while(curr != NULL){
        if(curr -> data % 2 == 0){
            if(even == NULL){
                even = curr;
                e = even;
            }else{
                e -> next = curr;
                e = e -> next;
            }
        }else{
            if(odd == NULL){
                odd = curr;
                o = odd;
            }else{
                o -> next = curr;
                o = o -> next;
            }
        }
        curr = curr -> next;
    }
    if(o == NULL || e == NULL){
        return;
    }
    e -> next = odd;
    o -> next = NULL;
    *head = even;
}

void printList(struct Node *node){
    while(node != NULL){
        printf("%d ", node -> data);
        node = node -> next;
    }
}

int main(){
    Node *head = new Node(1);
    head -> next = new Node(2);
    head -> next -> next = new Node(3);
    head -> next -> next -> next = new Node(4);
    head -> next -> next -> next -> next = new Node(5);
    head -> next -> next -> next -> next -> next = new Node(6);
    head -> next -> next -> next -> next -> next -> next = new Node(7);
    oddaftereven(&head);
    printList(head);
}