Adding methods in Swift - Mini Project: Build & Apply

Adding methods

📖 Scenario: You are creating a simple program to manage a car's information and actions.

🎯 Goal: Build a Swift program that defines a Car struct with properties and adds methods to display details and update the car's mileage.

📋 What You'll Learn

Create a struct named Car with properties make, model, and mileage

Add a method displayDetails() that prints the car's make, model, and mileage

Add a method drive(distance: Int) that increases the mileage by the given distance

Create an instance of Car with specific values

Call the methods to show the car details and update mileage

💡 Why This Matters

🌍 Real World

Managing objects like cars with properties and actions is common in apps for car rentals, maintenance tracking, or sales.

💼 Career

Understanding how to add methods to data structures is essential for building interactive and functional software in Swift development.

1

Create the Car struct with properties

Create a struct called Car with three properties: make and model of type String, and mileage of type Int. Then create a variable myCar of type Car with make set to "Toyota", model set to "Corolla", and mileage set to 50000.

Swift

// Your code here

Need a hint?

Use struct Car { ... } to define the structure. Add properties inside with var. Create myCar using the struct's initializer.

2

Add the displayDetails() method

Inside the Car struct, add a method called displayDetails() that prints the car's make, model, and mileage in this format: "Car: Toyota Corolla, Mileage: 50000".

Swift

struct Car {
    var make: String
    var model: String
    var mileage: Int

    // Add displayDetails() method here
}

var myCar = Car(make: "Toyota", model: "Corolla", mileage: 50000)

Need a hint?

Define a func displayDetails() inside Car. Use print with string interpolation to show the details.

3

Add the drive(distance:) method

Inside the Car struct, add a method called drive(distance: Int) that increases the mileage property by the given distance. Remember to mark the method as mutating because it changes the struct's property.

Swift

struct Car {
    var make: String
    var model: String
    var mileage: Int

    func displayDetails() {
        print("Car: \(make) \(model), Mileage: \(mileage)")
    }

    // Add mutating drive(distance:) method here
}

var myCar = Car(make: "Toyota", model: "Corolla", mileage: 50000)

Need a hint?

Use mutating func drive(distance: Int) to change mileage. Add the distance to mileage inside the method.

4

Use the methods and print the output

Call myCar.displayDetails() to print the initial details. Then call myCar.drive(distance: 150) to add 150 to the mileage. Finally, call myCar.displayDetails() again to print the updated details.

Swift

struct Car {
    var make: String
    var model: String
    var mileage: Int

    func displayDetails() {
        print("Car: \(make) \(model), Mileage: \(mileage)")
    }

    mutating func drive(distance: Int) {
        mileage += distance
    }
}

var myCar = Car(make: "Toyota", model: "Corolla", mileage: 50000)

// Call methods below

Need a hint?

Call displayDetails() before and after calling drive(distance: 150) on myCar.