Autoclosures (@autoclosure) in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a function parameter as an autoclosure.

Swift

func logIfTrue(_ predicate: [1]) {
    if predicate() {
        print("Condition is true")
    }
}

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

A() -> Bool

BBool

C@escaping () -> Bool

D@autoclosure () -> Bool

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to add '@autoclosure' before the closure type.

Using just 'Bool' instead of a closure type.

Using '@escaping' which is not needed here.

The @autoclosure attribute automatically wraps an expression into a closure, so the parameter type must be '@autoclosure () -> Bool'.

2fill in blank

medium

Complete the code to call the function with an autoclosure parameter.

Swift

logIfTrue([1] > 5)

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A3 + 4

B3 > 4

C7

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a Boolean literal directly without an expression.

Passing a value that is not a Boolean expression.

You can pass an expression like '3 + 4' directly to an autoclosure parameter; it will be wrapped automatically.

3fill in blank

hard

Fix the error in the function declaration to correctly use @autoclosure.

Swift

func check(_ condition: [1]) {
    if condition() {
        print("Checked true")
    }
}

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

A@autoclosure () -> Bool

BBool

C() -> Bool

D@escaping () -> Bool

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Bool' instead of a closure type.

Using '@escaping' which is not needed here.

The parameter must be declared as '@autoclosure () -> Bool' to use autoclosure correctly.

4fill in blank

hard

Fill both blanks to declare a function with an autoclosure parameter and call it correctly.

Swift

func evaluate(_ expression: [1]) {
    print("Result is \(expression())")
}
evaluate([2])

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A@autoclosure () -> Int

B5 * 3

C5 + 3

DInt

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Int' instead of a closure type for the parameter.

Passing a value without an expression.

The parameter must be '@autoclosure () -> Int' and the call passes an expression like '5 * 3' which is wrapped automatically.

5fill in blank

hard

Fill all three blanks to create a function with an autoclosure and escaping parameter, then call it.

Swift

func storeCondition(_ condition: [1], completion: @escaping () -> Void) {
    if condition() {
        completion()
    }
}

let conditionClosure: [2] = [3] > 10

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

A@autoclosure () -> Bool

B() -> Bool

C15

D20

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Bool' instead of closure types.

Assigning a raw value instead of an expression to the closure variable.

The function parameter uses '@autoclosure () -> Bool', the variable is a closure '() -> Bool', and the expression '20 > 10' is assigned to it.