Actor isolation concept in Swift - Mini Project: Build & Apply

Understanding Actor Isolation in Swift

📖 Scenario: Imagine you are building a simple app that keeps track of a bank account balance. To keep the balance safe from being changed by multiple parts of the app at the same time, you use Swift's actor to protect the balance.

🎯 Goal: You will create an Account actor that holds a balance. Then, you will add a method to deposit money safely. Finally, you will print the updated balance.

📋 What You'll Learn

Create an actor named Account with a balance property of type Int.

Add a method deposit(amount: Int) inside the actor to add money to the balance.

Create an instance of Account named myAccount.

Call the deposit(amount: 100) method on myAccount.

Print the updated balance using await to access the actor's property.

💡 Why This Matters

🌍 Real World

Actors help keep data safe in apps where many parts run at the same time, like banking apps or games.

💼 Career

Understanding actor isolation is important for writing safe, modern Swift code that avoids bugs from data conflicts.

1

Create the Account actor with a balance

Create an actor named Account with a property balance set to 0.

Swift

actor Account {
    // Your code here
}

Need a hint?

Use the actor keyword to define the actor and add a variable balance initialized to 0.

2

Add a deposit method to the Account actor

Inside the Account actor, add a func deposit(amount: Int) that adds amount to balance.

Swift

actor Account {
    var balance: Int = 0

    // Your code here
}

Need a hint?

Define a function deposit that takes amount and adds it to balance.

3

Create an instance of Account and deposit money

Create a constant myAccount as an instance of Account. Then call myAccount.deposit(amount: 100) using await.

Swift

actor Account {
    var balance: Int = 0

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

// Your code here

Need a hint?

Create myAccount with Account() and call deposit with await.

4

Print the updated balance from the actor

Print the updated balance of myAccount using await and print.

Swift

actor Account {
    var balance: Int = 0

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

let myAccount = Account()
await myAccount.deposit(amount: 100)

// Your code here

Need a hint?

Use print("Balance is \(await myAccount.balance)") to show the balance.