public void initiate()
    {
        /*screen */
        category = new Category();
        dairy = new Dairy();
        veg = new Vegetables();
        bakery = new Bakery();
        wine = new Wine();
        mycart = new MyCart();
        checkout = new CheckOut();
        
        /*Commands*/
        
        gocategory = new ScreenCommand(category);
        godairy = new ScreenCommand(dairy);
        goveg = new ScreenCommand(veg);
        gobakery = new ScreenCommand(bakery);
        gowine = new ScreenCommand(wine);
        gocart = new ScreenCommand(mycart);
        gocheckout = new ScreenCommand(checkout);
        
        /*history */
        history = new ArrayList<GroceryScreen>();
        
        this.current = category;
        this.display();
    }