Even Odd Linked List

#include <iostream>
using namespace std;

class node{
         public:
            int data; 
             node*next;
             
             node(int data ){
                 this->data=data;
                 next=NULL;
             }
 };
 
   node*takeinput(){
       
           int data;
           cin>>data;
           node*head=NULL;
           node*tail=NULL;
           while(data!=-1){
               node*newnode=new node(data);
               if(head==NULL){
                   head=newnode;
                   tail=newnode;
               }
               else{
                   tail->next=newnode;
                   tail=newnode;
               }
               cin>>data;
           }
           return head;
   }
   
   node*evenodd(node*head){
                node*oddhead=NULL;
                node*oddtail=NULL;
                node*evenhead=NULL;
                node*eventail=NULL;
                
      if(head==NULL || head->next==NULL){
          return head;
      }
      
       while(head!=NULL)
       {
           if(head->data%2!=0) {
                
          if(oddhead==NULL && oddtail==NULL)
          {
                   oddhead=head;
                   oddtail=head;
          }
          else
          {
              oddtail->next=head;
              oddtail=head;
          }
               }
           else{
       if(evenhead==NULL && eventail==NULL)
       {
                  evenhead=head;
                  eventail=head;
       }
       else
       {
                eventail->next=head;
                eventail=head;
       }
               } 
           head=head->next;    
                
      }
            if(oddhead==NULL){
                 return evenhead;
             }  
             else if(evenhead==NULL){
                 return oddhead;
             }   
             else{ 
        oddtail->next=evenhead;
        eventail->next=NULL;
        return oddhead;
        }
                
   }
   
    void print(node*head){
           while(head!=NULL){
               cout<<head->data<<" ";
               head=head->next;
           }
    }
int main() {

       node*head=takeinput();
       head=evenodd(head);
       print(head);
    return 0;
}