Functions returning tuples in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a function that returns a tuple with two integers.

Swift

func getCoordinates() -> [1] {
    return (10, 20)
}

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

A(Int, Int)

BString

CInt

DVoid

Attempts:

3 left

💡 Hint

Common Mistakes

Using just Int as return type instead of a tuple.

Using String as return type when the function returns numbers.

The function returns a tuple of two integers, so the return type must be (Int, Int).

2fill in blank

medium

Complete the code to call the function and store the returned tuple.

Swift

let position: [1] = getCoordinates()

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

A(Int, Int)

BInt

CString

DDouble

Attempts:

3 left

💡 Hint

Common Mistakes

Using Int instead of a tuple type for the variable.

Using String or Double which do not match the tuple.

The variable position must have the same tuple type as the function's return type, which is (Int, Int).

3fill in blank

hard

Fix the error in the function return type to correctly return a tuple with named elements.

Swift

func getUser() -> [1] {
    return (name: "Alice", age: 30)
}

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

A(String, Int)

B(name: String, age: Int)

CString

DInt

Attempts:

3 left

💡 Hint

Common Mistakes

Using unnamed tuple type (String, Int) when names are present.

Using just String or Int as return type.

The function returns a tuple with named elements, so the return type must include the names: (name: String, age: Int).

4fill in blank

hard

Fill both blanks to extract the tuple elements into variables.

Swift

let user = getUser()
let [1] = user.name
let [2] = user.age

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

AuserName

BuserAge

Cname

Dage

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same names as tuple elements which can cause confusion.

Using unrelated variable names.

We create new variables userName and userAge to hold the tuple's name and age values.

5fill in blank

hard

Fill all three blanks to define a function returning a tuple and call it correctly.

Swift

func [1]() -> (x: Int, y: Int) {
    return (x: 5, y: 10)
}

let point = [2]()
print("x is \(point.[3])")

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

AmakePoint

Cx

Dy

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatching function name and call.

Accessing the wrong tuple element.

The function is named makePoint, called as makePoint(), and the tuple element x is accessed to print its value.

Practice

1. What does a Swift function returning a tuple allow you to do?

easy

A. Return only one value

B. Return values only as dictionaries

C. Return values only as arrays

D. Return multiple values grouped together

Solution

1. Step 1: Understand tuple return type

   Functions returning tuples can send back multiple values grouped as one compound value.

2. Step 2: Compare with other return types

   Unlike arrays or dictionaries, tuples keep related values together without extra structure.

3. Final Answer:

   Return multiple values grouped together -> Option D

4. Quick Check:

   Functions returning tuples = multiple grouped values [OK]

Hint: Tuples bundle multiple return values simply [OK]

Common Mistakes:

• Thinking functions can return only one value
• Confusing tuples with arrays or dictionaries
• Assuming tuples must have named elements

2. Which of the following is the correct syntax for a Swift function returning a tuple with named elements x and y as Int?

easy

A. func getCoordinates() -> (x Int, y Int) { return (10, 20) }

B. func getCoordinates() -> (x: Int, y: Int) { return (10, 20) }

C. func getCoordinates() -> (Int x, Int y) { return (10, 20) }

D. func getCoordinates() -> (x: Int; y: Int) { return (10, 20) }

Solution

1. Step 1: Check tuple syntax in return type

   Named tuple elements use the format (name: Type, name: Type), so (x: Int, y: Int) is correct.

2. Step 2: Verify return statement matches tuple

   Returning (10, 20) matches the tuple structure with two Int values.

3. Final Answer:

   func getCoordinates() -> (x: Int, y: Int) { return (10, 20) } -> Option B

4. Quick Check:

   Named tuple syntax = (name: Type, ...) [OK]

Hint: Use colon between name and type in tuple [OK]

Common Mistakes:

• Using type before name in tuple elements
• Separating tuple elements with semicolon instead of comma
• Omitting names or using wrong punctuation

3. What is the output of this Swift code?

func minMax(numbers: [Int]) -> (min: Int, max: Int) {
    var currentMin = numbers[0]
    var currentMax = numbers[0]
    for number in numbers[1...] {
        if number < currentMin { currentMin = number }
        if number > currentMax { currentMax = number }
    }
    return (currentMin, currentMax)
}

let result = minMax(numbers: [3, 7, 2, 9, 4])
print(result.min, result.max)

medium

A. 2 9

B. 3 7

C. 9 2

D. Error: tuple elements not accessible

Solution

1. Step 1: Trace min and max calculation

   Start with first number 3 as min and max. Iterate over 7, 2, 9, 4 updating min to 2 and max to 9.

2. Step 2: Access tuple elements by name

   Returned tuple has named elements min and max, so result.min is 2 and result.max is 9.

3. Final Answer:

   2 9 -> Option A

4. Quick Check:

   min = 2, max = 9 [OK]

Hint: Tuple elements accessed by name like properties [OK]

Common Mistakes:

• Confusing min and max values
• Trying to access tuple elements by index instead of name
• Forgetting to start loop from second element

4. Identify the error in this Swift function returning a tuple:

func divide(_ a: Int, _ b: Int) -> (quotient: Int, remainder: Int) {
    let q = a / b
    let r = a % b
    return q, r
}

medium

A. Return statement syntax is incorrect for tuple

B. Division by zero error possible

C. Tuple elements must be unnamed

D. Function parameters must be named

Solution

1. Step 1: Check return statement syntax

   Returning multiple values as a tuple requires parentheses: return (q, r), not return q, r.

2. Step 2: Confirm tuple element names are allowed

   Named tuple elements in return type are valid; parameters can be unnamed as shown.

3. Final Answer:

   Return statement syntax is incorrect for tuple -> Option A

4. Quick Check:

   Return tuple with parentheses [OK]

Hint: Use parentheses around tuple values in return [OK]

Common Mistakes:

• Omitting parentheses in return tuple
• Assuming parameters must be named
• Ignoring possible division by zero (not asked here)

5. You want to write a Swift function that returns the sum, average, and count of an array of Ints as a tuple with named elements. Which of these implementations correctly does this?

hard

A. func stats(numbers: [Int]) -> (Int, Int, Int) {
let sum = numbers.reduce(0, +)
let count = numbers.count
let avg = sum / count
return (sum, avg, count)
}

B. func stats(numbers: [Int]) -> (sum: Int, avg: Int, count: Int) {
let sum = numbers.reduce(0, +)
let count = numbers.count
let avg = sum / count
return (sum, avg, count)
}

C. func stats(numbers: [Int]) -> (sum: Int, avg: Double, count: Int) {
let sum = numbers.reduce(0, +)
let count = numbers.count
let avg = Double(sum) / Double(count)
return (sum, avg, count)
}

D. func stats(numbers: [Int]) -> (sum: Int, avg: Double, count: Int) {
let sum = numbers.reduce(0, +)
let count = numbers.count
let avg = sum / count
return (sum, avg, count)
}

Solution

1. Step 1: Check return type matches values

   Return type must be named tuple (sum: Int, avg: Double, count: Int). Correct implementation declares this exactly.

2. Step 2: Verify average calculation

   Average requires Double conversion: Double(sum) / Double(count) to get precise floating-point result, avoiding integer truncation.

3. Step 3: Confirm return statement matches tuple

   return (sum, avg, count) aligns with named elements in order and type.

4. Final Answer:

   func stats(numbers: [Int]) -> (sum: Int, avg: Double, count: Int) { let sum = numbers.reduce(0, +) let count = numbers.count let avg = Double(sum) / Double(count) return (sum, avg, count) } -> Option C

5. Quick Check:

   named tuple + Double(sum)/Double(count) [OK]

Hint: Match tuple element types exactly, convert for average [OK]

Common Mistakes:

• Using Int for average causing integer division
• Mismatching tuple element names and return values
• Omitting type conversion for average calculation