# Checkpoint

The code we just studied in class, slightly expanded and with an application program, is available to download.

# Validating Inputs

Edit the `Program.cs` file of the project you previously download so that:

- User entering a value different from `A`, `a`, `H`, `h`, `O` and `o` would be asked again, and asked as long as they do not give a valid answer,
- User entering a credit score not between 300 and 850, or that is not an integer, would be asked again, and asked as long as they do not give a valid answer,
- User entering an amount needed or a downpaiment that is not a decimal, or is a negative decimal, would be asked again, and asked as long as they do not give a valid answer.
- (Optional) Use the ToLower() or ToUpper() methods of the `char` class to make the program more readable (you will be able to greatly simplify the `if` statement).