Actor declaration syntax in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the basic syntax to declare an actor in Swift?

Use the keyword actor followed by the actor's name and curly braces. For example:<br>

actor MyActor {
    // actor code here
}

beginner

Can an actor in Swift have properties and methods?

Yes, actors can have properties and methods just like classes. These help manage state safely in concurrent code.

intermediate

How do you mark a method inside an actor as asynchronous?

You add the async keyword after the method's parameter list and before the return type. For example:<br>

func fetchData() async -> String {
    // code
}

intermediate

Why use actors instead of classes for concurrency in Swift?

Actors protect their internal state by serializing access, preventing data races in concurrent environments.

beginner

How do you create an instance of an actor?

You create it like a class instance using the initializer:<br><pre>let myActor = MyActor()</pre>

Which keyword is used to declare an actor in Swift?

A actor

B class

C struct

D enum

The actor keyword declares an actor type in Swift.

What is the main benefit of using actors in Swift?

A They serialize access to their internal state to prevent data races.

B They allow multiple threads to access state simultaneously.

C They replace functions with asynchronous calls.

D They automatically optimize memory usage.

Actors serialize access to their internal state, preventing data races in concurrent code.

How do you mark a method inside an actor as asynchronous?

A No special keyword is needed.

B Add the <code>async</code> keyword before the return type.

C Use the <code>async</code> keyword after the method name.

D Add the <code>await</code> keyword before the method name.

Methods that perform asynchronous work inside actors are marked with async before the return type.

How do you create an instance of an actor named DataManager?

A new DataManager()

B actor dm = DataManager()

C let dm = actor DataManager()

D let dm = DataManager()

Actors are instantiated like classes using the initializer syntax.

Can actors in Swift have stored properties?

A No, actors cannot have any properties.

B No, actors can only have computed properties.

C Yes, actors can have stored properties.

D Only static properties are allowed.

Actors can have stored properties to hold their internal state.

Explain how to declare an actor in Swift and why you would use one.

Think about how actors help with safe access to data when many things happen at once.

Describe how asynchronous methods work inside an actor and how you declare them.

Remember that async methods let you wait for work without blocking the whole program.