Task and TaskGroup in iOS Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a simple asynchronous task that prints a message.

iOS Swift

Task {
    print([1])
}

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

ATask.sleep(1_000_000_000)

BHello from Task!

Cprint("Hello from Task!")

D"Hello from Task!"

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put quotes around the string.

Trying to print without a string argument.

The print function requires a string argument in quotes. Option D correctly provides a string literal.

2fill in blank

medium

Complete the code to create a TaskGroup that runs two tasks concurrently.

iOS Swift

Task {
    await withTaskGroup(of: Void.self) { group in
        group.addTask {
            print("Task 1")
        }
        group.addTask {
            print([1])
        }
    }
}

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

Aprint("Task 2")

BTask 2

C"Task 2"

DTask.sleep(1_000_000_000)

Attempts:

3 left

💡 Hint

Common Mistakes

Missing quotes around the string.

Trying to call print inside print.

Inside the print function, the argument must be a string literal with quotes. Option C is correct.

3fill in blank

hard

Fix the error in the TaskGroup code by completing the blank with the correct keyword to wait for all tasks.

iOS Swift

Task {
    [1] withTaskGroup(of: Int.self) { group in
        group.addTask { 1 }
        group.addTask { 2 }
    }
}

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

Aawait

Basync

Ctry

Dyield

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'async' instead of 'await'.

Omitting the keyword entirely.

The 'await' keyword is needed to wait for the TaskGroup to complete its tasks asynchronously.

4fill in blank

hard

Fill both blanks to create a TaskGroup that returns the sum of two asynchronous tasks.

iOS Swift

let sum = await withTaskGroup(of: Int.self) { group in
    group.addTask { 5 }
    group.addTask { 10 }
    var total = 0
    for await [1] in group {
        total [2] [1]
    }
    return total
}

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Avalue

B+=

C-=

Ditem

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-=' instead of '+='.

Using a loop variable name not matching the code.

The loop variable should be 'value' to hold each task result, and '+=' adds it to total.

5fill in blank

hard

Fill all three blanks to create a TaskGroup that returns the maximum value from three asynchronous tasks.

iOS Swift

let maxValue = await withTaskGroup(of: Int.self) { group in
    group.addTask { 3 }
    group.addTask { 7 }
    group.addTask { 5 }
    var maxVal = Int.min
    for await [1] in group {
        if [1] [2] maxVal {
            maxVal = [1]
        }
    }
    return maxVal
}

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

Aresult

B>

C<

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' in the comparison.

Using inconsistent variable names.

The loop variable is 'result'. We compare if result > maxVal, then update maxVal with result.