Class declaration syntax in Swift - Step-by-Step Execution

Concept Flow - Class declaration syntax

Start

↓

Write 'class' keyword

↓

Name the class

↓

Open curly brace '{'

↓

Declare properties and methods

↓

Close curly brace '}'

↓

Class declared

↓

End

This flow shows the steps to declare a class in Swift: start with the keyword, name it, add properties/methods inside braces, then finish.

Execution Sample

Swift

class Dog {
    var name: String
    func bark() {
        print("Woof!")
    }
}

Declares a class named Dog with a property 'name' and a method 'bark' that prints 'Woof!'.

Execution Table

Step	Action	Code Part	Result
1	Start class declaration	class Dog {	Class named Dog begins
2	Declare property	var name: String	Property 'name' of type String added
3	Declare method	func bark() { ... }	Method 'bark' added
4	Method body	print("Woof!")	Prints 'Woof!' when called
5	Close class	}	Class Dog declaration ends

💡 Class declaration ends after closing brace '}'

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
class Dog	Not declared	Declared with property 'name'	Added method 'bark'	Complete class Dog

Key Moments - 3 Insights

Why do we need the curly braces '{' and '}'?

Curly braces mark where the class starts and ends, so Swift knows which properties and methods belong to the class (see execution_table steps 1 and 5).

What does 'var name: String' mean inside the class?

It declares a property called 'name' that will hold text (a String) for each Dog object (see execution_table step 2).

What happens inside the 'bark' method?

When 'bark' is called, it runs the code inside its braces, printing 'Woof!' to the screen (see execution_table step 4).

Visual Quiz - 3 Questions

Look at the execution table, what is the result after step 3?

A Class Dog is closed

B Only the class name is declared

C Class Dog has a property and a method declared

D The method 'bark' prints 'Woof!'

💡 Hint

Check the 'Result' column at step 3 in the execution_table

At which step does the class declaration end?

A Step 4

B Step 5

C Step 2

D Step 3

💡 Hint

Look for the closing brace '}' in the 'Code Part' column in execution_table

If we remove the curly braces, what would happen?

A Swift would not know where the class starts and ends

B The method 'bark' would print twice

C The class would still be declared correctly

D The property 'name' would become a method

💡 Hint

Refer to key_moments about curly braces and execution_table steps 1 and 5

Concept Snapshot

Swift class declaration syntax:
class ClassName {
    var propertyName: Type
    func methodName() {
        // code
    }
}
Use curly braces to group properties and methods inside the class.

Full Transcript

This visual execution shows how to declare a class in Swift. First, write the keyword 'class' followed by the class name. Then open curly braces to start the class body. Inside, declare properties like 'var name: String' and methods like 'func bark()'. The method contains code to run when called, here printing 'Woof!'. Finally, close the class with a curly brace. Each step builds the class structure so Swift understands it.