program that convert decimal number into binary

#include<iostream>
using namespace std;
struct decimal
{
  int num;
  decimal *next;
 
}*head;
void convert( int num)
{ decimal  * d= new decimal ;

     while(num!=0)
    
     {
     decimal  * d= new decimal ;
        d->next=NULL;
     if(head==NULL)
{
            d->num=num%2;
      head=d;
      num/=2;
     }
     else {
      d->num=num%2;
      d->next=head;
      head=d;
   
      num/=2;
     }
   
}}
void display()
{
 decimal * temp;
 temp=head;

 while(temp!=NULL)
 {
   cout<<temp->num;
   temp=temp->next;
 }
}

int main()
{  head =NULL;
     int num;
     cout<<"Enter the number please "<<endl;
     cin>>num;
     cout<<"The decimal in binary =";
    convert(num);
    display();
}