class

struct Resolution {
  var width = 0
  var height = 0
}
class VideoMode {
  var resolution = Resolution()
  var interlaced = false
  var frameRate = 0.0
  var name: String?
}

The Resolution structure definition and the VideoMode class definition only describe the appearance of Resolution or VideoMode, create an instance of the structure or class:

let resolution = Resolution(width: 1920)
let someVideoMode = VideoMode()

use data type

class Student {
  var name: String
  var year: Int
  var gpa: Double
  var honors: Bool
}

Use default property values

class Student {
  var name = ""
  var gpa = 0.0
  var honors = false
}

Suppose we have a BankAccount class:

class BankAccount {
  var balance = 0.0
  func deposit(amount: Double) {
    balance += amount
  }
  func withdraw(amount: Double) {
    balance -= amount
  }
}

SavingsAccount extends BankAccount class

class SavingsAccount: BankAccount {
  varinterest = 0.0
  func addInterest() {
    let interest = balance \*0.005
    self. deposit(amount: interest)
  }
}

The new SavingsAccount class (subclass) automatically gets all the characteristics of the BankAccount class (superclass). Additionally, the SavingsAccount class defines an .interest property and an .addInterest() method.

var ferris = Student()
ferris.name = "Ferris Bueller"
ferris.year = 12
ferris.gpa = 3.81
ferris.honors = false

class Person {
  var name = ""
  var age = 0
}
var sonny = Person()
// sonny is now an instance of Person

class Player {
  var name: String
  init(name: String) {
    self.name = name
  }
}
var player1 = Player(name: "Tomoko")
var player2 = player1
player2.name = "Isabella"
print(player1.name) // Isabella
print(player2.name) // Isabella