Generic enums in Rust - Mini Project: Build & Apply

Using Generic Enums in Rust

📖 Scenario: You are building a simple program to store different types of values using a generic enum in Rust. This helps you keep related data together in one place, like storing either a number or a text message.

🎯 Goal: Create a generic enum called Value that can hold either a number or a text. Then, create instances of this enum with different types and print their contents.

📋 What You'll Learn

Define a generic enum named Value with two variants: Number and Text.

Create a variable num_value of type Value<i32> holding the number 42.

Create a variable text_value of type Value<String> holding the text "Hello".

Use a match statement to print the contents of both variables.

💡 Why This Matters

🌍 Real World

Generic enums let you store different types of related data in one variable, useful in many programs like handling user input, configuration options, or messages.

💼 Career

Understanding generic enums is important for Rust developers to write flexible and reusable code, a common requirement in systems programming and software development.

1

Define the generic enum Value

Define a generic enum called Value with a type parameter T. It should have two variants: Number holding a value of type T, and Text holding a value of type T.

Rust

// Define the generic enum Value with variants Number and Text
// Your code here

Hint

Use enum Value<T> and define variants with T as the type.

2

Create variables using the generic enum

Create a variable called num_value of type Value<i32> holding the number 42. Also create a variable called text_value of type Value<String> holding the text "Hello".

Rust

enum Value {
    Number(T),
    Text(T),
}

// Create num_value and text_value variables
// Your code here

Hint

Use Value::Number(42) and Value::Text(String::from("Hello")) to create the variables.

3

Use match to access enum contents

Write a match statement to check the variant of num_value. If it is Number, print "Number: {value}". If it is Text, print "Text: {value}". Do the same for text_value.

Rust

enum Value {
    Number(T),
    Text(T),
}

let num_value: Value = Value::Number(42);
let text_value: Value = Value::Text(String::from("Hello"));

// Use match to print num_value and text_value
// Your code here

Hint

Use match variable { Value::Number(val) => ..., Value::Text(val) => ... } to check variants.

4

Print the enum contents

Add println! statements inside the match arms to print the values of num_value and text_value exactly as shown: Number: 42 and Text: Hello.

Rust

enum Value {
    Number(T),
    Text(T),
}

let num_value: Value = Value::Number(42);
let text_value: Value = Value::Text(String::from("Hello"));

match num_value {
    Value::Number(val) => println!("Number: {}", val),
    Value::Text(val) => println!("Text: {}", val),
}

match text_value {
    Value::Number(val) => println!("Number: {}", val),
    Value::Text(val) => println!("Text: {}", val),
}

// Your code here

Hint

Make sure the printed output matches exactly: Number: 42 and Text: Hello.