Base class and subclass in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a base class in Swift?

A base class is a class that other classes can inherit from. It provides common properties and methods that subclasses can use or override.

beginner

What is a subclass in Swift?

A subclass is a class that inherits from a base class. It can use or change the properties and methods of the base class and add new ones.

beginner

How do you declare a subclass in Swift?

You declare a subclass by writing the subclass name followed by a colon and the base class name. For example: <code>class Dog: Animal { }</code>

intermediate

What does the override keyword do in Swift subclasses?

The <code>override</code> keyword tells Swift that you want to replace a method or property from the base class with your own version in the subclass.

beginner

Can a subclass access properties of its base class?

Yes, a subclass can access and use the properties and methods of its base class unless they are marked as private.

How do you declare a subclass named Car that inherits from a base class Vehicle in Swift?

A class Car: Vehicle { }

B class Car inherits Vehicle { }

C class Car extends Vehicle { }

D class Car < Vehicle { }

In Swift, you declare a subclass by writing the subclass name followed by a colon and the base class name.

What keyword must you use to replace a base class method in a subclass?

A override

B replace

C super

D extend

The override keyword is used to replace a method or property from the base class in the subclass.

If a property in the base class is marked private, can the subclass access it?

A Yes, always

B Only if subclass is in the same file

C No, never

D Only if marked <code>override</code>

Private properties are not accessible by subclasses.

Which of these is true about subclasses?

A They cannot add new properties

B They can only use base class methods without changes

C They must have the same name as the base class

D They can add new properties and override methods

Subclasses can add new properties and override existing methods from the base class.

What is the main benefit of using a base class and subclass?

A To write the same code multiple times

B To organize code and reuse common features

C To make code slower

D To prevent any changes in code

Base classes and subclasses help organize code and reuse common properties and methods.

Explain what a base class and a subclass are in Swift and how they relate to each other.

Think about a parent and child relationship in real life.

Describe how you would override a method in a Swift subclass and why you might want to do that.

Imagine changing a recipe to make it your own.