Convenience initializers in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a convenience initializer that sets a default name.

Swift

class Person {
    var name: String
    init(name: String) {
        self.name = name
    }
    convenience init() {
        self.init(name: [1])
    }
}

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

A"Unknown"

BUnknown

Cname

Dself.name

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to use quotes around the string.

Trying to assign directly to self.name in the convenience initializer.

The convenience initializer calls the designated initializer with a default string "Unknown" as the name.

2fill in blank

medium

Complete the convenience initializer to set both name and age with default values.

Swift

class Person {
    var name: String
    var age: Int
    init(name: String, age: Int) {
        self.name = name
        self.age = age
    }
    convenience init() {
        self.init(name: [1], age: 0)
    }
}

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

Aname

BNoName

C"NoName"

Dself.name

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a variable name instead of a string literal.

Omitting quotes around the string.

The convenience initializer calls the designated initializer with a default name "NoName" and age 0.

3fill in blank

hard

Fix the error in the convenience initializer call to the designated initializer.

Swift

class Rectangle {
    var width: Double
    var height: Double
    init(width: Double, height: Double) {
        self.width = width
        self.height = height
    }
    convenience init(size: Double) {
        self.init(width: [1], height: size)
    }
}

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

Asize

Bself.size

Cwidth

Dheight

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'self.size' which is not defined.

Using 'width' which is not a parameter here.

The convenience initializer uses the parameter 'size' for both width and height by passing it directly.

4fill in blank

hard

Fill both blanks to complete the convenience initializer that calls the designated initializer with default values.

Swift

class Car {
    var make: String
    var year: Int
    init(make: String, year: Int) {
        self.make = make
        self.year = year
    }
    convenience init() {
        self.init(make: [1], year: [2])
    }
}

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

A"Toyota"

B2020

C2010

D"Honda"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string without quotes for make.

Using a year value that is not the default.

The convenience initializer calls the designated initializer with default make "Toyota" and year 2020.

5fill in blank

hard

Fill all three blanks to create a convenience initializer that sets default values and calls the designated initializer.

Swift

class Book {
    var title: String
    var author: String
    var pages: Int
    init(title: String, author: String, pages: Int) {
        self.title = title
        self.author = author
        self.pages = pages
    }
    convenience init() {
        self.init(title: [1], author: [2], pages: [3])
    }
}

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

A"Untitled"

B"Unknown"

C100

D"Anonymous"

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up author and title values.

Using strings without quotes.

The convenience initializer calls the designated initializer with default title "Untitled", author "Unknown", and pages 100.