Hashable example

Hash-Part3.swift

struct Key {
  let id: Int
  let title: String
}

extension Key: Hashable {
  func hash(into hasher: inout Hasher) {
    hasher.combine(self.id)
  }
}

var dict = [Key: Int]()
let key1 = Key(id: 1, title: "Key1")
let key2 = Key(id: 2, title: "Key2")
dict[key1] = 1058
dict[key2] = 368
print(dict.count) // 2
print(key1 == key2) // false