Returning functions from functions in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return a function that adds 5 to its input.

Kotlin

fun addFive(): (Int) -> Int {
    return { x -> x + 5 }
}

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

A{ x -> x + 5 }

B{ x -> x - 5 }

C{ x -> x * 5 }

D{ x -> x / 5 }

Attempts:

3 left

💡 Hint

Common Mistakes

Returning a lambda that subtracts or multiplies instead of adding.

Not returning a lambda at all.

The function must return a lambda that adds 5 to the input number.

2fill in blank

medium

Complete the code to return a function that multiplies its input by 3.

Kotlin

fun multiplyByThree(): (Int) -> Int {
    return { x -> x * 3 }
}

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

A{ x -> x / 3 }

B{ x -> 3 - x }

C{ x -> x + 3 }

D{ x -> x * 3 }

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition or subtraction instead of multiplication.

Dividing instead of multiplying.

The returned lambda multiplies the input by 3.

3fill in blank

hard

Fix the error in the code to correctly return a function that subtracts 2 from its input.

Kotlin

fun subtractTwo(): (Int) -> Int {
    return { x -> x - 2 }
}

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

A{ x -> x + 2 }

B{ x -> x - 2 }

C{ x -> 2 - x }

D{ x -> x * 2 }

Attempts:

3 left

💡 Hint

Common Mistakes

Adding 2 instead of subtracting.

Subtracting input from 2 instead of the other way around.

The lambda must subtract 2 from the input number.

4fill in blank

hard

Fill both blanks to create a function that returns a function which adds a given number to its input.

Kotlin

fun adder(n: Int): (Int) -> Int {
    return { x -> x [1] n[2] }
}

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

A*

B-

C+

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using subtraction or multiplication instead of addition.

Adding extra operators after n.

The function returns a lambda that adds n to x using the + operator. The second blank is a space to complete the expression.

5fill in blank

hard

Fill all three blanks to create a function that returns a function which multiplies its input by a given number and then adds another number.

Kotlin

fun multiplyAndAdd(multiplier: Int, addend: Int): (Int) -> Int {
    return { x -> x [1] multiplier [2] addend[3] }
}

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

A*

B+

C-

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using subtraction or division instead of addition.

Mixing the order of operations.

The lambda multiplies x by multiplier using * and then adds addend using +. The last blank is a space to complete the expression.