Associated values per case in Swift - Mini Project: Build & Apply

Using Associated Values in Swift Enums

📖 Scenario: Imagine you are building a simple app to track different types of notifications a user can receive. Each notification type can carry extra information.

🎯 Goal: You will create an enum with associated values to represent different notification types and then write code to handle them.

📋 What You'll Learn

Create an enum called Notification with cases that have associated values

Add a variable to hold a sample notification

Use a switch statement to extract and print the associated values

Print the final message describing the notification

💡 Why This Matters

🌍 Real World

Enums with associated values are useful to represent different types of data that share a category but carry extra information, like notifications, messages, or API responses.

💼 Career

Understanding enums with associated values is important for Swift developers building iOS apps, as it helps write clear and safe code for handling varied data types.

1

Create the Notification enum with associated values

Create an enum called Notification with these cases and associated values exactly: message(String), friendRequest(from: String), and photoLike(photoID: Int, liker: String).

Swift

# Your code here

Need a hint?

Use enum keyword and define cases with parentheses for associated values.

2

Create a variable with a sample notification

Create a variable called notification and assign it the Notification.friendRequest(from: "Alice") value.

Swift

enum Notification {
    case message(String)
    case friendRequest(from: String)
    case photoLike(photoID: Int, liker: String)
}

# Your code here

Need a hint?

Use var notification = Notification.friendRequest(from: "Alice") exactly.

3

Use a switch to handle the notification and extract associated values

Write a switch statement on notification with cases for .message(let text), .friendRequest(let from), and .photoLike(let photoID, let liker). Inside each case, create a variable description with a string describing the notification using the associated values.

Swift

enum Notification {
    case message(String)
    case friendRequest(from: String)
    case photoLike(photoID: Int, liker: String)
}

var notification = Notification.friendRequest(from: "Alice")

switch notification {
    // Your code here
}

Need a hint?

Use switch notification and pattern match each case with let to get associated values.

4

Print the notification description

Write a print statement to display the description variable.

Swift

enum Notification {
    case message(String)
    case friendRequest(from: String)
    case photoLike(photoID: Int, liker: String)
}

var notification = Notification.friendRequest(from: "Alice")

var description = ""
switch notification {
case .message(let text):
    description = "Message: \(text)"
case .friendRequest(let from):
    description = "Friend request from \(from)"
case .photoLike(let photoID, let liker):
    description = "Photo \(photoID) liked by \(liker)"
}

print(description)  # Your code here

Need a hint?

Use print(description) to show the message.