Classes

// Using data types:
class Student {
  var name: String
  var year: Int
  var gpa: Double
  var honors: Bool
}


// Using default property values:
class Student {
  var name = ""
  var year = 0
  var gpa = 0.0
  var honors = false
}

class Person {
  var name = ""
  var age = 0
}

var sonny = Person()

// sonny is now an instance of Person

var ferris = Student()

ferris.name = "Ferris Bueller"
ferris.year = 12
ferris.gpa = 3.81
ferris.honors = false

class Fruit {
  var hasSeeds = true 
  var color: String

  init(color: String) {
    self.color = color
  }
}

let apple = Fruit(color: "red")

// Suppose we have a BankAccount class:

class BankAccount {
  var balance = 0.0

  func deposit(amount: Double) {
    balance += amount
  }

  func withdraw(amount: Double) {
    balance -= amount
  }
}


// And we want a new SavingsAccount class that inherits from BankAccount:

class SavingsAccount: BankAccount {
  var interest = 0.0

  func addInterest() {
    let interest = balance * 0.005
    self.deposit(amount: interest)
  }
}

// Here, the new SavingsAccount class (subclass) automatically gains all of the characteristics of BankAccount class (superclass). In addition, the SavingsAccount class defines a .interest property and a .addInterest() method.

// Suppose we have a BankAccount class:

class BankAccount {
  var balance = 0.0

  func deposit(amount: Double) {
    balance += amount
  }

  func withdraw(amount: Double) {
    balance -= amount
  }
}


// Suppose we want a new SavingsAccount class and we want to override the .withdraw() method from its superclass BankAccount:

class SavingsAccount: BankAccount {
  var interest = 0.0
  var numWithdraw = 0

  func addInterest() {
    let interest = balance * 0.01
    self.deposit(amount: interest)
  }

  override func withdraw(amount: Double) {
    balance -= amount
    numWithdraw += 1
  }
}