Class declaration syntax in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the basic syntax to declare a class in Kotlin?

Use the <code>class</code> keyword followed by the class name and curly braces. Example: <pre>class MyClass { }</pre>

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How do you declare a primary constructor in a Kotlin class?

Add the constructor parameters directly after the class name in parentheses. Example: <pre>class Person(val name: String, var age: Int)</pre>

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What keyword is used to declare a class in Kotlin?

The keyword is class. It tells Kotlin you are defining a new class.

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Can a Kotlin class have no body? Show an example.

Yes, if there is no need for properties or functions inside, you can omit the curly braces. Example: <pre>class Empty</pre>

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How do you declare properties inside a Kotlin class primary constructor?

Use <code>val</code> for read-only and <code>var</code> for mutable properties inside the constructor parentheses. Example: <pre>class Car(val brand: String, var year: Int)</pre>

Which keyword starts a class declaration in Kotlin?

A class

B struct

C object

D fun

The class keyword is used to declare a class in Kotlin.

How do you declare a primary constructor with two properties in Kotlin?

A class Person(name: String, age: Int)

B class Person(val name: String, var age: Int)

C class Person { val name: String; var age: Int }

D fun Person(val name: String, var age: Int)

Primary constructor parameters with val or var declare properties directly.

Can a Kotlin class be declared without curly braces?

A Only if it has a primary constructor

B No, curly braces are always required

C Yes, if the class has no body

D Only for abstract classes

If the class has no body, curly braces can be omitted.

What does val mean in a Kotlin class constructor?

A Read-only property

B Mutable property

C Function parameter

D Local variable

val declares a read-only property.

Which of these is NOT a valid Kotlin class declaration?

A class Animal(val species: String)

B class Vehicle { val wheels = 4 }

C class Book(var title: String, var author: String)

D class Person function(name: String)

Option D uses invalid syntax; function keyword is not used in class declaration.

Explain how to declare a simple Kotlin class with a primary constructor that has two properties.

Think about how you write the class name and put properties inside parentheses.

Describe when you can omit the curly braces in a Kotlin class declaration.

Consider if the class has no properties or functions inside.