What technique is used to ensure the zip code is numeric in the provided example?

What technique is used to ensure the zip code is numeric in the provided example?

• A. Wrap int(zipCode) in a try/except block
• B. Use a regular expression to validate digits
• C. Convert without any checks
• D. Assume input is numeric by default

Answer: (A)

Using exception handling to validate numeric input by attempting a conversion to an integer is the approach being tested. The idea is to try to convert the zip code to an int; if the input is truly numeric, the conversion succeeds and you know the value is numeric. If the input isn’t numeric, the conversion raises an error, which you catch to handle invalid input gracefully (prompt the user again, log the issue, etc.). This pattern makes the check explicit and controllable, rather than assuming input is valid or relying on separate checks that might miss edge cases. Other options would either bypass handling (converting without checks), rely on assumptions (assuming input is numeric by default), or use a separate validation step like a regex. While a regex can ensure only digits are present, the example in question uses the conversion-with-exception pattern, which is why that choice is the best fit here.

Using exception handling to validate numeric input by attempting a conversion to an integer is the approach being tested. The idea is to try to convert the zip code to an int; if the input is truly numeric, the conversion succeeds and you know the value is numeric. If the input isn’t numeric, the conversion raises an error, which you catch to handle invalid input gracefully (prompt the user again, log the issue, etc.). This pattern makes the check explicit and controllable, rather than assuming input is valid or relying on separate checks that might miss edge cases.

Other options would either bypass handling (converting without checks), rely on assumptions (assuming input is numeric by default), or use a separate validation step like a regex. While a regex can ensure only digits are present, the example in question uses the conversion-with-exception pattern, which is why that choice is the best fit here.