Why classes exist alongside structs in Swift - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a struct in Swift.

Swift

struct Person { [1] 
    var name: String
}

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A(

B<

C[

D{

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses or square brackets instead of curly braces.

The struct body must be enclosed in curly braces { }.

2fill in blank

medium

Complete the code to create an instance of a class in Swift.

Swift

let person = [1]()

Drag options to blanks, or click blank then click option'

APerson

Bstruct Person

Cclass Person

Dfunc Person

Attempts:

3 left

💡 Hint

Common Mistakes

Including 'class' or 'struct' keywords when creating an instance.

To create an instance, use the class name followed by parentheses.

3fill in blank

hard

Fix the error in the code to correctly copy a struct instance.

Swift

var person1 = Person(name: "Alice")
var person2 = [1]

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Aperson1()

B&person1

Cperson1

DPerson

Attempts:

3 left

💡 Hint

Common Mistakes

Using & to reference the variable, which is not needed for structs.

Assigning one struct instance to another copies the value.

4fill in blank

hard

Fill both blanks to show how classes behave differently from structs when assigned.

Swift

class PersonClass {
    var name: String
    init(name: String) {
        self.name = name
    }
}

var personA = PersonClass(name: "Bob")
var personB = [1]
personB.name = "Charlie"
print(personA.name) // [2]

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ApersonA

B"Bob"

C"Charlie"

DPersonClass(name: "Bob")

Attempts:

3 left

💡 Hint

Common Mistakes

Thinking classes copy values like structs do.

Assigning a class instance copies the reference, so changing personB changes personA.

5fill in blank

hard

Fill all three blanks to complete the code that demonstrates why classes exist alongside structs.

Swift

struct Point {
    var x: Int
    var y: Int
}

class Circle {
    var center: [1]
    var radius: Int
    init(center: [2], radius: Int) {
        self.center = center
        self.radius = radius
    }
}

let centerPoint = Point(x: 0, y: 0)
let circle1 = Circle(center: centerPoint, radius: 5)
let circle2 = circle1
circle2.center.x = 10
print(circle1.center.x) // [3]

Drag options to blanks, or click blank then click option'

APoint

BCircle

C0

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Assuming changing circle2.center.x changes circle1.center.x because Circle is a class.

The class Circle holds a struct Point. Changing circle2.center.x does not affect circle1.center.x because Point is a value type.