0struct Person: Equatable, Hashable, Comparable { let name: String let age: Int static func == (lhs: Person, rhs: Person) -> Bool { lhs.name == rhs.name && lhs.age == rhs.age } func hash(into hasher: inout Hasher) { hasher.combine(name) hasher.combine(age) } static func < (lhs: Person, rhs: Person) -> Bool { lhs.age < rhs.age } } let p1 = Person(name: "Alice", age: 30) let p2 = Person(name: "Bob", age: 25) print(p1 == p2) print(p1 < p2)
| Step | Action | Evaluation | Result |
|---|---|---|---|
| 1 | Create p1 | Person(name: "Alice", age: 30) | p1 = Person(name: "Alice", age: 30) |
| 2 | Create p2 | Person(name: "Bob", age: 25) | p2 = Person(name: "Bob", age: 25) |
| 3 | Check p1 == p2 | p1.name == p2.name && p1.age == p2.age | false ("Alice" != "Bob") |
| 4 | Check p1 < p2 | p1.age < p2.age | false (30 < 25 is false) |
| 5 | Hash p1 | Combine name and age | hash value computed |
| 6 | Hash p2 | Combine name and age | hash value computed |
| 7 | End | No more actions | Program ends |
| Variable | Start | After Step 1 | After Step 2 | Final |
|---|---|---|---|---|
| p1 | nil | Person(name: "Alice", age: 30) | Person(name: "Alice", age: 30) | Person(name: "Alice", age: 30) |
| p2 | nil | nil | Person(name: "Bob", age: 25) | Person(name: "Bob", age: 25) |
Equatable: implement static func == to compare equality. Hashable: implement func hash(into:) to provide hash value. Comparable: implement static func < to define order. Use these to compare, hash, and sort your types easily.
Which protocol in Swift allows you to check if two instances of a type are equal using ==?
==.Which of the following is the correct way to declare a struct Person that conforms to Equatable and Hashable?
struct Person: ??? {
var name: String
var age: Int
}What will be the output of the following Swift code?
struct Item: Comparable {
var value: Int
static func < (lhs: Item, rhs: Item) -> Bool {
return lhs.value < rhs.value
}
}
let items = [Item(value: 3), Item(value: 1), Item(value: 2)]
let sortedValues = items.sorted().map { $0.value }
print(sortedValues)< operator compares value properties to sort ascending.Identify the error in this Swift struct that tries to conform to Hashable:
struct Book: Hashable {
var title: String
var pages: Int
func hash(into hasher: inout Hasher) {
hasher.combine(title)
}
}title is combined; pages is missing, causing incorrect hashing.You want to create a struct Player that can be stored in a Set, compared for equality, and sorted by score descending. Which protocols should Player conform to, and how should you implement the sorting?
< operator to compare scores descending by reversing comparison.Pass the test and this pattern moves unknown strong while earning +1 Grip toward your certificate.