Question

Is there a data type I can use to store a single digit, but nothing else. i.e. one of 0 – 9 and nothing else.

I know I could use short, int or long, but it’s for the design of an api and I want to be clear that the user should only give me a single digit.

Answer 1

Sounds like a good candidate for an enum type.

public enum Digit
{
    Zero, 
    One,
    Two,
    Three, 
    Four, 
    Five, 
    Six,
    Seven,
    Eight, 
    Nine
}

Benefits:

1. Easily understood.
2. Directly convertible to and from its underlying type

Disadvantage:

1. Theoretically possible to create instances that don’t belong in the [0 – 9] range since an enum instance can take any value of the underlying type.