Calculator: division by zero error, how do I fix that?-CodePudding

Division by zero error, how do I fix that?(zero/zero = error). How can I implement it into the calculator function.

import logging
def calculate(choice):
    if choice == "1":
        logging.info("Add")
        num1 = input("Enter the first number")
        num2 = input("Enter the second number") 
        return int(num1)   int(num2)
    if choice == "2":
        logging.info("Subtract")
        num1 = input("Enter the first number")
        num2 = input("Enter the second number")
        return int(num1) - int(num2)
    if choice == "3":
        logging.info("Multiply")
        num1 = input("Enter the first number")
        num2 = input("Enter the second number")
        return int(num1) * int(num2)
    if choice == "4":
        logging.info("Divide")
        num1 = input("Enter the first number")
        num2 = input("Enter the second number")
        return int(num1) / int(num2)       `#division by zero error, how do I fix that?`
choice = input("Choose 1 - Add 2 - Subtract 3 - Multiply 4 - Divide")
result = calculate(choice)
print(result)```

CodePudding user response：

You indicate in the comments that you want the user to be shown a message when they try to divide by zero.

Python already prints a message - the exception and traceback:

>>> 0 / 0
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ZeroDivisionError: division by zero

but you may also 'catch' this exception and provide your own, more user-friendly message. Notice Python helpfully tells you the kind of exception it threw, the ZeroDivisionError. That is the type of exception you want to catch. E.g.

try:
     0 / 0
except ZeroDivisionError:
     print("Cannot divide by zero")

Produces the output:

Cannot divide by zero

You can read in more detail about the try ... except statement in the Python docs.

CodePudding user response：

If you just want it to return "Error", then you can use this code for part 4:

if choice == "4":
        logging.info("Divide")
        num1 = input("Enter the first number")
        num2 = input("Enter the second number")
        return int(num1) / int(num2) if num2 != 0 else "Error, division by 0 is impossible."

I'm guessing this is what you mean, I've basically put in an if statement in so that "Error" is returned if the divisor is 0.

Alternatively you could use a try except solution.

CodePudding user response：

Here is one of the option to allow user to enter second number if it's 0 or type exit to exit:

if choice == "4":
    logging.info("Divide")
    num1 = input("Enter the first number")
    num2 = input("Enter the second number")
    if num2 == "0":
        # If second number is 0, loop until user enter non-zero number of exit
        print ("Second number cannot be zero")
        while (True):
            num2 = input("Enter non-zero number or type 'exit' to exit")
            if (num2 != "0" or num2 == "exit"):
                break
                
    return int(num1) / int(num2) if num2 != "exit" else None