21 lines
561 B
Rust
21 lines
561 B
Rust
// If an option may return null - or nothing - in Rust, it's wrapped
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// in an Optional which may return either the type of object specified
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// in <> or None. We can check this using .is_some() and .is_none() on
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// the Option.
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fn check_number(num: &Option<u8>) {
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if num.is_none() {
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println!("Number is: None");
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} else {
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println!("Number is: {}", num.unwrap());
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}
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}
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fn main() {
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let mut possible_number: Option<u8> = None;
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check_number(&possible_number);
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possible_number = Some(31);
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check_number(&possible_number);
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}
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