FAQ: Properties and Access Control - Using Property Observers

Frequently Asked Questions Swift FAQ
1

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This community-built FAQ covers the “Using Property Observers” exercise from the lesson “Properties and Access Control”.

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This exercise can be found in the following Codecademy content:

[BETA] Build iOS Apps with SwiftUI

FAQs on the exercise Using Property Observers

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2

Hey, I have a question. Seems like I’m the first one…
Im on number 8 and I don’t understand why the last function in this code doesn’t work and how to fix it.
I’m guessing it has something to do with the type of level of access. Though again, idk how to resolve this.

Error message:
SwiftBank.swift:28:26: error: instance member ‘finalDepositWithBonus’ cannot be used on type ‘SwiftBank’; did you mean to use a value of this type instead?
balance += SwiftBank.finalDepositWithBonus()
~~~~~~~~~ ^

struct SwiftBank {
  // password
  private let password : String
  // init
  init(password : String){
    self.password = password
  }
  // valid password?
  private func isValid(_ enteredPassword: String) -> Bool{
    if enteredPassword == password {
      return true
    } else {
      return false
    }
  }
  
  // balance
  private var balance: Double = 0
  // declare type property
  static let depositBonusRate: Double = 0.01
  // calculate total deposit amount
  private func finalDepositWithBonus(deposit: Double) -> Double {
   return deposit + (deposit * SwiftBank.depositBonusRate)
  }
  // Make Deposit
  mutating func makeDeposit(depositAmount: Double){
      balance += SwiftBank.finalDepositWithBonus()
  }
}
4

This is how I got it to work:

  private func finalDepositWithBonus(fromInitialDeposit deposit: Double) -> Double
    {
    return deposit + (deposit * SwiftBank.depositBonusRate)
    }
  // Make Deposit
  mutating func makeDeposit(ofAmount depositAmount: Double)
    {
    balance += finalDepositWithBonus(fromInitialDeposit: depositAmount)
    }
5

The below code worked for me after spending some time on it:

// #1-3: Define structure and password
struct SwiftBank {
 private let password: String
 init(password: String){
   self.password = password
 }

// #4: Check if the user is authorized
private func isValid(_ enteredPassword: String) -> Bool {
  if enteredPassword == password {
   return true 
   } else {
   return false
  }
 }

// #5: Enable deposits
 private var balance: Double = 0

// #6: Set the rate of the bonus
 static let depositBonusRate = 0.01

// #7: Calculate total deposits
 private func finalDepositWithBonus(fromInitialDeposit deposit: Double) -> Double {
  return deposit + (deposit * SwiftBank.depositBonusRate)
 }

// #8: Making Deposit
mutating func makeDeposit(ofAmount depositAmount: Double){
   let depositWithBonus = finalDepositWithBonus (fromInitialDeposit: depositAmount)
   
   print("Making a deposit of $\(depositAmount) with a bonus rate. The final amount deposited is $\(depositWithBonus).")
 
   balance += depositWithBonus
 }
}