Queue Implementation using Linked List in C++

#include<iostream.h>
#include<conio.h>
struct node
{
 int data;
 struct node *link;
};
class queue
{
 struct node *front,*rear,*ptr;
 public:
 queue(){
 rear=NULL;
 front=NULL;
 }
 void enqueue(int);
 void dqueue();
 void display();
};
  void queue::enqueue(int data)
{
  ptr=new node;
  if(rear==NULL)
   { front=ptr;
   }
   else
   {
    rear->link=ptr;
    ptr->link=NULL;
    }
    rear=ptr;
  rear->data=data;
  cout<<"\n>>";
      }
  void queue::dqueue()
{
int item;
 if(front==NULL)
 cout<<"\nQueue is empty:\n";
 else
 {
   item=front->data;
if(front==rear)
   {
   front=NULL;
   rear=NULL;
   }
else
{
   ptr=front;
   front=front->link;
   delete ptr;
   }
   cout<<"deleted elmnt : "<<item;
 }
}

  void queue::display()
{
ptr=front;
 if(front==NULL)
    cout<<"\nQueue is empty";
 else
    {
cout<<"\nElements in queue are: ";
     while(ptr!=NULL)
{
  cout<<ptr->data<<"|";
  ptr=ptr->link;
}
    }
}
  void main()
{
queue q;
int ch,data;
clrscr();
cout<<"\n........MENU..........\n";
cout<<"1 . enqueue\n";
cout<<"2 . dqueue\n";
cout<<"3 . display\n";
cout<<"4 . exit\n";
while(1)
{
cout<<"\n Enter your choice: ";
cin>>ch;
switch(ch)
   {
    case 1:
    cout<<"\n Enter the element: ";
    cin>>data;
    q.enqueue(data);break;


    case 2:
    q.dqueue();break;


    case 3:
    q.display();break;


    case 4:
    ch=5;break;
    default:
    cout<<"\nInvalid selection\n";break;
    }
    if(ch==5)
    break;
}
       getch();
}