从另一个文件调用数学 Function 的问题

Question

I'm currently working on a unit conversion calculator, and wanted to make it smoother by calling the math functions from a different file. Currently, Celsius -> Fahrenheit (CF) is put in 'func.py', like this:

# This file has all the math functions that get called by main.py when needed.
# Also, VARIABLES!
num = 0
typ = 0

def CF():
  tota = (num * 9/5) + 32
  print("Answer: " + str(tota) + " degrees Fahrenheit")

And the code to call it in main.py looks like this:

if (typ == str('C-F')):
  num = int(input("Enter the temperature in Celcius: "))
  num = num
  CF()

I figure that I imported something wrong, but I've edited the import function several times now. I'm not looking for some type of complete correction, I wish for somebody to tell me what I did wrong, so that I can fix it. I used repl.it, if it helps. Even if someone can tell me that it's possible, it'll help.

I couldn't find anything on websites like GeeksforGeeks, which is my main source on research.

Answer 1

You need to work with function parameters and returns (see this for a tutorial).

# func.py
def CF(num):
  return (num * 9/5) + 32

# main.py
if (typ == str('C-F')):
  num = int(input("Enter the temperature in Celcius: "))
  tota = CF(num)
  print("Answer: " + str(tota) + " degrees Fahrenheit")

Answer 2

This is very odd:

def CF():

You're relying on num being defined at module scope within its module. Much better to spell it this way, so you're passing in an argument:

def cf(num):

Over in main.py you're doing this, which isn't helpful:

num = num

Much better to pass it in:

cf(num)

---

The big concept you've been missing is you have two different modules, and each one has a num variable. They are different. Changing one won't automatically affect the other.

Use function parameters instead.