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📘 Rust Beginner Course · Lesson 4 of 6

“`rust
struct Line { item: String, qty: u32, rate: f64 }
impl Line { fn amount(&self) -> f64 { self.qty as f64 * self.rate } }

enum Status { Paid, Pending { days: u32 }, Cancelled }
fn label(s: &Status) -> String {
match s {
Status::Paid => “Paid”.into(),
Status::Pending { days } => format!(“Pending {days} days”),
Status::Cancelled => “Cancelled”.into(),
}
}
“`

match must cover every variant, so adding a new status forces you to handle it everywhere. The project file uses an enum for row errors.

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Practice

Add the Line struct and Status enum to a project and print labels.