Type constraints with protocol conformance in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a generic function that accepts any type conforming to the Comparable protocol.

Swift

func findMax<T: [1]>(_ a: T, _ b: T) -> T {
    return a > b ? a : b
}

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

ACodable

BComparable

CEquatable

DHashable

Attempts:

3 left

💡 Hint

Common Mistakes

Using Equatable instead of Comparable, which only supports equality checks.

Using Codable or Hashable which do not provide comparison operators.

The generic type T must conform to Comparable to use the > operator.

2fill in blank

medium

Complete the code to constrain the generic type to the Hashable protocol.

Swift

func checkAndHash<T: [1]>(_ value: T) -> Int {
    return value.hashValue
}

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

AHashable

BCodable

CComparable

DEquatable

Attempts:

3 left

💡 Hint

Common Mistakes

Using Equatable instead of Hashable, as Equatable lacks hashValue.

Using Codable or Comparable which do not provide hashValue.

The generic type T must conform to Hashable to use hashValue. Hashable inherits from Equatable.

3fill in blank

hard

Fix the error in the generic function declaration by filling the correct protocol conformance.

Swift

func compareItems<T: [1]>(_ first: T, _ second: T) -> Bool {
    return first == second
}

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

ACodable

BComparable

CEquatable

DHashable

Attempts:

3 left

💡 Hint

Common Mistakes

Using Comparable which supports ordering but not just equality.

Using Codable or Hashable which do not define == operator.

The equality operator == requires the type to conform to Equatable.

4fill in blank

hard

Fill both blanks to declare a generic function where T conforms to Codable and U conforms to Hashable.

Swift

func processItems<T: [1], U: [2]>(item1: T, item2: U) {
    print(item1)
    print(item2.hashValue)
}

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

ACodable

BEquatable

CHashable

DComparable

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the protocols for T and U.

Using Comparable or Equatable incorrectly.

The first generic type T conforms to Codable, and the second generic type U must conform to Hashable to access hashValue.

5fill in blank

hard

Fill all three blanks to create a generic function where T conforms to Comparable, U conforms to Equatable, and V conforms to Codable.

Swift

func genericFunction<T: [1], U: [2], V: [3]>(a: T, b: U, c: V) {
    if a > a {
        print(b == b)
    }
    print(c)
}

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

AComparable

BEquatable

CCodable

DHashable

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing which protocol supports which operator.

Using Hashable instead of Codable for printing.

The generic type T must conform to Comparable to use >. U must conform to Equatable to use ==. V conforms to Codable.