measurement with python from foot and inch to meter and centimeter - measure

Question

Hello guys I want to make a program that invert the measurement At the first, the user input two or three numbers and the inverting is going to meter and centimeter but it's not showing the correct answer the only answer is 0 I would be so thankful if you help me
foot = inch = 0
foot_to_meter = foot_to_centimeter = inch_to_meter = inch_to_centimeter =0
def read():
foot = int(input('foot?'))
inch = int(input('inch?'))
def calculater():
foot_to_meter = 0.3048 * foot
foot_to_centimeter = 100 * foot_to_meter
# inch_to_meter = 12 * foot
inch_to_meter = (1.0/12) * 0.3048* inch
inch_to_centimeter = 100 * inch_to_meter
def write():
print(f'foot is {foot_to_centimeter} centimeter and {foot_to_meter} meter')
print(f'inch is {inch_to_centimeter} centimeter and {inch_to_centimeter} meter')
# print('the' foot 'is' meter 'meter' 'and' 'foot is' foot_to_centimeter)
# print('the' inch 'is' meter 'meter' "and" 'icnh is' inch_to_centimeter )
def main():
read()
calculater()
write()
main()

Answer 1

If you assign values to a variable in python it does not automatically use global scoped variables but instead assigns them to locally scoped variables. Note, for read-only functions global variables are used automatically.
To fix your issue you can use the global keyword ahead of assignments to global variables.
foot = inch = 0
foot_to_meter = foot_to_centimeter = inch_to_meter = inch_to_centimeter =0
def read():
global foot, inch
foot = int(input('foot?'))
inch = int(input('inch?'))
def calculater():
global foot_to_meter, foot_to_centimeter, inch_to_meter, inch_to_centimeter
foot_to_meter = 0.3048 * foot
foot_to_centimeter = 100 * foot_to_meter
# inch_to_meter = 12 * foot
inch_to_meter = (1.0/12) * 0.3048* inch
inch_to_centimeter = 100 * inch_to_meter
def write():
print(f'foot is {foot_to_centimeter} centimeter and {foot_to_meter} meter')
print(f'inch is {inch_to_centimeter} centimeter and {inch_to_centimeter} meter')
# print('the' foot 'is' meter 'meter' 'and' 'foot is' foot_to_centimeter)
# print('the' inch 'is' meter 'meter' "and" 'icnh is' inch_to_centimeter )
def main():
read()
calculater()
write()
main()
I would like to note that global variables often can lead to troubles when working with bigger codebases and importing modules, that's why I would advise to not use them if not absolutely necessary.
You can rewrite your program like this:
def read():
foot = int(input('foot?'))
inch = int(input('inch?'))
return foot, inch
def calculater(foot, inch):
foot_to_meter = 0.3048 * foot
foot_to_centimeter = 100 * foot_to_meter
# inch_to_meter = 12 * foot
inch_to_meter = (1.0/12) * 0.3048* inch
inch_to_centimeter = 100 * inch_to_meter
return foot_to_meter, foot_to_centimeter, inch_to_meter, inch_to_centimeter
def write(foot_to_meter, foot_to_centimeter, inch_to_meter, inch_to_centimeter):
print(f'foot is {foot_to_centimeter} centimeter and {foot_to_meter} meter')
print(f'inch is {inch_to_centimeter} centimeter and {inch_to_centimeter} meter')
# print('the' foot 'is' meter 'meter' 'and' 'foot is' foot_to_centimeter)
# print('the' inch 'is' meter 'meter' "and" 'icnh is' inch_to_centimeter )
def main():
foot, inch = read()
foot_to_meter, foot_to_centimeter, inch_to_meter, inch_to_centimeter = calculater(foot, inch)
write(foot_to_meter, foot_to_centimeter, inch_to_meter, inch_to_centimeter)
main()