Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

iOS Swift Closures Functions as First Class Citizens Higher Order Functions

Torben Schulz
Torben Schulz
262 Points
Posted by Torben Schulz
Torben Schulz
262 Points

What is wrong with my solution ? It does run in playground.

'Rechecking Work' does print the error, which was present before and does not recheck my code

higherOrderFunctions.swift 
/** 
  For this code challenge, let’s define a math operation as a function that 
  carries out some work on two integers and returns an integer as well. An 
  example is the function below, `differenceBetweenNumbers`, which takes two 
  integers and calculates the difference between the numbers. After calculating, 
  it returns the difference.
*/

func differenceBetweenNumbers(a: Int, b:Int) -> (Int) {
  return a - b
}

// Enter your code below

// Enter your code below
func mathOperation(operation:(Int,Int) -> Int , a: Int , b: Int) -> (Int)
{
    return operation(a,b)
}


let difference = mathOperation(differenceBetweenNumbers , 3 , 2 )

1 Answer

agreatdaytocode
agreatdaytocode
24,757 Points

Try this:

func mathOperation(someOperationFunc: (Int, Int) -> Int, a: Int, b: Int) -> Int {
    return someOperationFunc(a, b)
}

let difference = mathOperation(differenceBetweenNumbers, 26, 22)
Torben Schulz
Torben Schulz
262 Points
Torben Schulz
Torben Schulz
262 Points

Thank you for your answer. The parenthesis around the return type were wrong. So is there a semantic difference, writing the return type in parenthesis or without? Or is it just the parser you wrote, which does not expect it ?