Protocol inheritance in Swift - Mini Project: Build & Apply

Protocol inheritance

📖 Scenario: Imagine you are designing a simple app to manage different types of vehicles. Some vehicles can be driven, some can fly, and some can do both. You want to organize these capabilities using Swift protocols.

🎯 Goal: You will create protocols to represent different vehicle capabilities and use protocol inheritance to combine them. Then, you will create a struct that conforms to the combined protocol and print its capabilities.

📋 What You'll Learn

Create a protocol called Drivable with a method drive() that prints "Driving on the road".

Create a protocol called Flyable with a method fly() that prints "Flying in the sky".

Create a protocol called Vehicle that inherits from both Drivable and Flyable.

Create a struct called FlyingCar that conforms to Vehicle and implements both drive() and fly() methods.

Create an instance of FlyingCar and call both drive() and fly() methods.

💡 Why This Matters

🌍 Real World

Using protocol inheritance helps organize related capabilities in apps that manage different types of objects, like vehicles with multiple functions.

💼 Career

Understanding protocol inheritance is important for Swift developers to write clean, reusable, and scalable code in iOS app development.

1

Create the base protocols

Create a protocol called Drivable with a method drive() that prints "Driving on the road". Also create a protocol called Flyable with a method fly() that prints "Flying in the sky".

Swift

# Create protocol Drivable with method drive() that prints "Driving on the road"
# Create protocol Flyable with method fly() that prints "Flying in the sky"

Need a hint?

Protocols define methods without implementation. You will add the print statements when you implement these methods in a struct.

2

Create a protocol that inherits from both

Create a protocol called Vehicle that inherits from both Drivable and Flyable.

Swift

protocol Drivable {
    func drive()
}

protocol Flyable {
    func fly()
}

# Create protocol Vehicle that inherits from Drivable and Flyable

Need a hint?

Use a colon and list the protocols separated by commas to inherit multiple protocols.

3

Create a struct that conforms to Vehicle

Create a struct called FlyingCar that conforms to Vehicle. Implement the drive() method to print "Driving on the road" and the fly() method to print "Flying in the sky".

Swift

protocol Drivable {
    func drive()
}

protocol Flyable {
    func fly()
}

protocol Vehicle: Drivable, Flyable {
}

# Create struct FlyingCar that conforms to Vehicle
# Implement drive() and fly() methods with print statements

Need a hint?

Implement both methods inside the struct with the exact print statements.

4

Create an instance and call the methods

Create an instance of FlyingCar called myFlyingCar. Call the drive() method and then the fly() method on myFlyingCar.

Swift

protocol Drivable {
    func drive()
}

protocol Flyable {
    func fly()
}

protocol Vehicle: Drivable, Flyable {
}

struct FlyingCar: Vehicle {
    func drive() {
        print("Driving on the road")
    }
    func fly() {
        print("Flying in the sky")
    }
}

# Create instance myFlyingCar of FlyingCar
# Call drive() and fly() methods on myFlyingCar

Need a hint?

Remember to create the instance with let and call the methods with dot notation.