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iOS Swift Closures Functions as First Class Citizens Higher Order Functions

Nick Grothe
Nick Grothe
3,461 Points
Posted by Nick Grothe
Nick Grothe
3,461 Points

I am following the instructions and getting no errors in the editor but I am not getting a pass - can you please help?

Here is my code:

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

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

let difference = mathOperation(differenceBetweenNumbers, 4, 3)

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
}

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

let difference = mathOperation(differenceBetweenNumbers, 2, 1)

1 Answer

Jhoan Arango
Jhoan Arango
14,575 Points
Jhoan Arango
Jhoan Arango
14,575 Points

Hello Nick:

I did some small changes to your code, and it passed, here are the changes.

The concept is the same, but for some reason it passes like this, even tho Xcode does not give you any errors with your code. 

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

let difference = mathOperation(differenceBetweenNumbers,4,5)
Nick Grothe
Nick Grothe
3,461 Points
Nick Grothe
Nick Grothe
3,461 Points

This worked thanks!