4.2. Enums and Pattern Matching

Introduction

I've learned about structs, so what's next in intermediate programming concepts?

How about enums and pattern matching? They're useful concepts in some programming languages!

Ooh, tell me more! Let's learn!

Alright! We'll use Rust as our programming language for this example.

Step 1: Defining an Enum

First, let's define an enum!

Enums are a way to define a custom data type that represents a set of named values. Here's an example:

enum TrafficLight {
    Red,
    Yellow,
    Green,
}

Step 2: Creating Enum Instances

Now, how do I create instances of an enum?

You can create instances like this:

let light = TrafficLight::Red;

Step 3: Using Pattern Matching with Enums

How do I use pattern matching with enums?

Pattern matching allows you to handle different enum values in a clear and concise way. Let's create a function that uses pattern matching with our TrafficLight enum!

fn traffic_light_duration(light: TrafficLight) -> u32 {
    match light {
        TrafficLight::Red => 60,
        TrafficLight::Yellow => 10,
        TrafficLight::Green => 30,
    }
}

Step 4: Displaying the Result

Time to see the result!

Here's an example of how to use the function:

fn main() {
    let light = TrafficLight::Yellow;
    let duration = traffic_light_duration(light);
    println!("The duration of the yellow light is {} seconds.", duration);
}

Output:

The duration of the yellow light is 10 seconds.

Conclusion

Great job! You’ve learned how to use enums and pattern matching in Rust. Enums are a helpful way to represent a set of named values, and pattern matching is a powerful tool for handling different cases. Keep exploring intermediate programming concepts and continue learning! 🎉