Type aliases for readability in Swift - Mini Project: Build & Apply

Type aliases for readability

📖 Scenario: You are working on a simple app that tracks distances in kilometers and miles. To keep your code clear and easy to understand, you want to use type aliases to give meaningful names to the distance values.

🎯 Goal: Create type aliases for Kilometers and Miles as Double. Then use these aliases to declare variables and convert between kilometers and miles.

📋 What You'll Learn

Create a type alias called Kilometers for Double

Create a type alias called Miles for Double

Declare a variable distanceInKm of type Kilometers with value 5.0

Declare a variable distanceInMiles of type Miles and convert distanceInKm to miles using the formula miles = kilometers * 0.621371

Print the value of distanceInMiles with a descriptive message

💡 Why This Matters

🌍 Real World

Type aliases are useful in real apps to make code clearer, especially when working with units like distances, times, or currencies.

💼 Career

Understanding type aliases helps you write readable and maintainable Swift code, a skill valued in iOS and macOS development jobs.

1

Create type aliases for distances

Create a type alias called Kilometers for Double and a type alias called Miles for Double.

Swift

// Create type aliases for Kilometers and Miles
// Your code here

Need a hint?

Use the typealias keyword followed by the new name and the existing type.

2

Declare a distance variable in kilometers

Declare a variable called distanceInKm of type Kilometers and set it to 5.0.

Swift

typealias Kilometers = Double
typealias Miles = Double

// Declare distanceInKm as Kilometers with value 5.0
// Your code here

Need a hint?

Use var distanceInKm: Kilometers = 5.0 to declare the variable.

3

Convert kilometers to miles

Declare a variable called distanceInMiles of type Miles and set it to distanceInKm multiplied by 0.621371.

Swift

typealias Kilometers = Double
typealias Miles = Double

var distanceInKm: Kilometers = 5.0

// Declare distanceInMiles as Miles by converting distanceInKm
// Your code here

Need a hint?

Multiply distanceInKm by 0.621371 and assign it to distanceInMiles.

4

Print the converted distance

Print the value of distanceInMiles with the message: "Distance in miles: " followed by the value.

Swift

typealias Kilometers = Double
typealias Miles = Double

var distanceInKm: Kilometers = 5.0
var distanceInMiles: Miles = distanceInKm * 0.621371

// Print the distanceInMiles with a descriptive message
// Your code here

Need a hint?

Use print("Distance in miles: \(distanceInMiles)") to show the result.