Enums

January 30, 2023

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An enum (or enumeration) represents data that is one of several possible variants. Each variant in the enum can optionally have data associated with it. An enumeration is declared using the enum keyword.

enum Fruit {
    Apple,
    Orange,
    Lemon,
    Mellon,
}

fn selection(fruit: Fruit) {
    match fruit {
        Fruit::Apple => println!("Selected the Apple fruit"),
        Fruit::Orange => println!("You chose the Orange fruit"),
        Fruit::Mellon => println!("You selected a Watermelon"),
        Fruit::Lemon => println!("Selected a Lemon fruit"),
    }
}

fn main() {
    let item1 = Fruit::Orange;
    selection(item1);

    let item2 = Fruit::Apple;
    selection(item2);

    let item3 = Fruit::Mellon;
    selection(item3);

    let item4 = Fruit::Lemon;
    selection(item4);
}

The output from the above example is shown below.

You chose the Orange fruit
Selected the Apple fruit
You selected a Watermelon
Selected a Lemon fruit