Base class and subclass in Swift - Mini Project: Build & Apply

Base class and subclass

📖 Scenario: You are creating a simple program to represent animals. Each animal has a name and can make a sound. You want to create a base class for general animals and a subclass for a specific animal type.

🎯 Goal: Build a base class called Animal with a property and a method, then create a subclass called Dog that changes the sound it makes.

📋 What You'll Learn

Create a base class Animal with a name property and a makeSound() method

Create a subclass Dog that inherits from Animal

Override the makeSound() method in Dog to print a dog-specific sound

Create an instance of Dog and print its sound

💡 Why This Matters

🌍 Real World

Understanding base classes and subclasses helps organize code when many objects share common features but behave differently.

💼 Career

Inheritance is a key concept in object-oriented programming used in app development, game programming, and software design.

1

Create the base class Animal

Create a base class called Animal with a name property of type String and an initializer that sets name. Add a method called makeSound() that prints "Some generic animal sound".

Swift

class Animal {
    var name: String
    
    // Your code here
}

Need a hint?

Remember to create an initializer init(name: String) to set the name property.

2

Create the subclass Dog

Create a subclass called Dog that inherits from Animal. Override the makeSound() method to print "Woof!".

Swift

class Animal {
    var name: String
    
    init(name: String) {
        self.name = name
    }
    
    func makeSound() {
        print("Some generic animal sound")
    }
}

// Your code here

Need a hint?

Use override keyword to change the behavior of makeSound() in the subclass.

3

Create an instance of Dog

Create a variable called myDog and assign it an instance of Dog with the name "Buddy".

Swift

class Animal {
    var name: String
    
    init(name: String) {
        self.name = name
    }
    
    func makeSound() {
        print("Some generic animal sound")
    }
}

class Dog: Animal {
    override func makeSound() {
        print("Woof!")
    }
}

// Your code here

Need a hint?

Use let myDog = Dog(name: "Buddy") to create the instance.

4

Call makeSound() on myDog

Call the makeSound() method on the myDog instance to print the dog's sound.

Swift

class Animal {
    var name: String
    
    init(name: String) {
        self.name = name
    }
    
    func makeSound() {
        print("Some generic animal sound")
    }
}

class Dog: Animal {
    override func makeSound() {
        print("Woof!")
    }
}

let myDog = Dog(name: "Buddy")

// Your code here

Need a hint?

Use myDog.makeSound() to call the method.