Null object: Difference between revisions

=={{header|Rust}}==

<lang rust>// If an option may return null - or nothing - in Rust, it's wrapped

// in an Optional which may return either the type of object specified

// in <> or None. We can check this using .is_some() and .is_none() on

// the Option.

fn check_number(num: &Option<u8>) {

if num.is_none() {

println!("Number is: None");

} else {

println!("Number is: {}", num.unwrap());

}

}

fn main() {

let mut possible_number: Option<u8> = None;

check_number(&possible_number);

possible_number = Some(31);

check_number(&possible_number);

}</lang>