ECS Calculate Tip

from tkinter import*
import tkinter.simpledialog
import tkinter.messagebox

root = Tk()
w = Label(root, text="Calculate Tip")
w.pack()

food = tkinter.simpledialog.askfloat("Food Price", "Please enter the cost for food.")

#subtotal is the total of the food and drinks
subtotal = food

#15% * the subtotal
tip = 0.15 * subtotal

#finish this line so it adds up the subtotal, tip and tax
total =

#this line prints out the tip and total value:
tkinter.messagebox.showinfo("Bill Summary", "Food: $" + str(food) +
    "\nSubtotal: $" + str(subtotal) +
    "\nTip: $" + str(tip) +
    "\nTotal: $" + str(total))


# Your are to finish writing this program that will calculate the tip
# for a restaurant bill.
#
# 1. Finish the code where you must calculate the total (it will not run
#    unitl you fix it).
# 2. Make the code calculate the tax for you use 8%.  Have it output it
#    and add it to the total.
# 3. Have the code take in the price of a drink.  Then add the drink
#    to your subtotal.  Make sure to output the price of the drink at the end.