CSCD 110

# This program uses value functions to do some conversions.
# Define our constant variables
# These are our menu options
F_TO_C = 1
C_TO_F = 2
F_TO_M = 3
M_TO_F = 4
EXTRA = 5
QUIT = 0
# We need a main function
def main():
choice = 7
while choice != QUIT:
display_menu() # Call to display our menu
choice = int(input("Please enter a menu choice: "))
if choice == F_TO_C:
temp = float(input("Please enter a temperature in degrees Fahrenheit."))
print(temp, "degrees Fahrenheit is equal to ", convert_to_celcius(temp),"degrees Celcius")

def convert_to_celcius(fahrenheit):
return (fahrenheit - 32) * 5/9
def display_menu():
print(" Menu")
print("1. Convert from Fahrenheit to Celsius.")
print("2. Convert from Celsius to Fahrenheit.")
print("3. Convert Feet to Meters.")
print("4. Convert Meters to Feet.")
print("5. Print a string backwards.")
print("0. Quit.")

Why does my menu function not display in the python shell? Plz Help.