version1-basic.py

#
# My awesome program! (basic version without integer input validation)
#

# ask the user how many cookies:

cookieCount = input("HOW MANY COOKIES DO YOU WANT TO MAKE? ")

# provide affirmative feedback to the user:

print "OK, CALCULATING RECIPE FOR " + str(cookieCount) + " COOKIES ..."

# calculate the recipe based on the user input:

sugarCups = round((cookieCount * (1.5 / 48)), 2) # should be 1.5 for a batch of 48 cookies
butterCups = round((cookieCount * (1.0 / 48)), 2) # should be 1 for a batch of 48 cookies
flourCups = round((cookieCount * (2.75 / 48)), 2) # should be 2.75 for a batch of 48 cookies

# communicate the recipe to the user:

print("  " + str(sugarCups) + " CUPS OF SUGAR")
print("  " + str(butterCups) + " CUPS OF BUTTER")
print("  " + str(flourCups) + " CUPS OF FLOUR")

version2-advanced.py

#
# My awesome program!
#

# ask the user how many cookies

cookieCount = input("HOW MANY COOKIES DO YOU WANT TO MAKE? ")
print "OK, CALCULATING RECIPE FOR " + str(cookieCount) + " COOKIES ..."

try:
    # make sure the user provided an integer number of cookies.
    # if cookieCount is not an integer or convertable into an integer, the rest of code in the "try" block will be skipped
    # ... and the "except" block will be executed instead
   int(cookieCount) # check if cookieCount is an integer

   # provide affirmative feedback to the user

   print "OK, CALCULATING RECIPE FOR " + str(cookieCount) + " COOKIES ..."

   # calculate the recipe based on the user input

   sugarCups = round((cookieCount * (1.5 / 48)), 2) # should be 1.5 for a batch of 48 cookies
   butterCups = round((cookieCount * (1.0 / 48)), 2) # should be 1 for a batch of 48 cookies
   flourCups = round((cookieCount * (2.75 / 48)), 2) # should be 2.75 for a batch of 48 cookies

   # communicate the recipe to the user

   print("  " + str(sugarCups) + " CUPS OF SUGAR")
   print("  " + str(butterCups) + " CUPS OF BUTTER")
   print("  " + str(flourCups) + " CUPS OF FLOUR")
except ValueError:
    # this block will be executed if any code within the "try" block throws an error of the type "ValueError", which is the kind of error that gets thrown when calling "int()" on a string
   print("OOPS, PLEASE PROVIDE AN INTEGER NUMBER OF COOKIES!")