Why async/await simplifies concurrent code in iOS Swift - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an asynchronous function in Swift.

iOS Swift

func fetchData() [1] {
  // code to fetch data
}

Drag options to blanks, or click blank then click option'

Aasync

Bawait

Cthrows

Dsync

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'await' instead of 'async' in the function declaration.

Using 'throws' which is for error handling, not async behavior.

In Swift, you declare an asynchronous function by adding the async keyword after the function signature.

2fill in blank

medium

Complete the code to call an asynchronous function using await.

iOS Swift

func load() async {
  let data = try? [1] fetchData()
}

Drag options to blanks, or click blank then click option'

Aawait

Basync

Casync await

Dtry

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'async' before the function call instead of 'await'.

Omitting the 'await' keyword causing compile errors.

To call an asynchronous function and wait for its result, use the await keyword before the function call.

3fill in blank

hard

Fix the error in the code by adding the missing keyword to handle asynchronous code.

iOS Swift

func process() [1] {
  let result = try? await fetchData()
}

Drag options to blanks, or click blank then click option'

Async

Bawait

Cthrows

Dasync

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to mark the function as async causes compile errors.

Trying to use await inside a synchronous function.

The function calling await must itself be marked async to handle asynchronous code properly.

4fill in blank

hard

Fill both blanks to create a task that runs asynchronous code concurrently.

iOS Swift

Task.[1] {
  let data = try? [2] fetchData()
}

Drag options to blanks, or click blank then click option'

Adetached

Bawait

Casync

Dsync

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'async' instead of 'await' inside the task.

Not using 'detached' to create a concurrent task.

Use Task.detached to start a new concurrent task, and await to wait for the async function inside it.

5fill in blank

hard

Fill all three blanks to define an async function that returns a string after awaiting another async call.

iOS Swift

func getMessage() [1] [2] -> String {
  let data = try? [3] fetchData()
  return data ?? "No data"
}

Drag options to blanks, or click blank then click option'

Aasync

Bawait

Cthrows

Dsync

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to mark the function as async and throws.

Not using await before the async function call.

The function is marked async and throws because it can throw errors. Inside, await is used to wait for the async call.