| 27 | Validating Inputs |
Large functions aren’t very usable or maintainable. It makes a lot of sense to break down the logic of a program into smaller functions that do one thing each. The program can then call these functions in sequence to perform the work.
Write a program that prompts for a first name, last name, employee ID, and ZIP code. Ensure that the input is valid according to these rules:
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The first name must be filled in.
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The last name must be filled in.
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The first and last names must be at least two characters long.
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An employee ID is in the format AA-1234. So, two letters, a hyphen, and four numbers.
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The ZIP code must be a number.
Display appropriate error messages on incorrect data.
Example Output
| | Enter the first name: J |
| | Enter the last name: |
| | Enter the ZIP code: ABCDE |
| | Enter an employee ID: A12-1234 |
| | "J" is not a valid first name. It is too short. |
| | The last name must be filled in. |
| | The ZIP code must be numeric. |
| | A12-1234 is not a valid ID. |
Or
| | Enter the first name: Jimmy |
| | Enter the last name: James |
| | Enter the ZIP code: 55555 |
| | Enter an employee ID: TK-421 |
| | There were no errors found. |
Constraints
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Create a function for each type of validation you need to write. Then create a validateInput function that takes in all of the input data and invokes the specific validation functions.
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Use a single output statement to display the outputs.
Challenges
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Use regular expressions to validate the input.
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Implement this as a GUI application or web application that gives immediate feedback when the fields lose focus.
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Repeat the process if the input is not valid.