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iOS Swift Closures Functions as First Class Citizens Higher Order Functions

Posted by George Brown
George Brown
2,039 Points

Help please?!!

Don't know how to input function into another function as a declaration

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



let difference =
Joseph Haddad
Joseph Haddad
16,246 Points
Joseph Haddad
Joseph Haddad
16,246 Points

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

// This function declaration takes a function as an input that takes two inputs as Ints and return an int as in :

diffFunc: (Int, Int) -> Int // which will be the differenceBetweenNumbers method in our case

// this function also takes two inputs a and b as the two numbers to perform the math operation specified by differenceBetweenNumbers which is subtraction in our case.

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

mathOperation(differenceBetweenNumbers, 3, 1) // should return 2