Passing function within function parameter swift

Passing function within function parameter swift

This is one of the powerful feature of swift. That’s called “function type” that means function itself is a type and you can pass this function to another function. For example (Int,Int) -> Int that means you can pass any such function which takes two integer parameters and returns an integer.

Below is a great example done by me, would be easy to understand the concept.

func addTwoNum(a:Int,b:Int) -> Int {
    return a+b
}
func mulTwoNum(a:Int,b:Int) -> Int {
    return a*b
}

func testFunc(adderFunc:(Int,Int)->Int,c:Int,d:Int) -> Int {
    let answer = adderFunc(c,d)
    return answer
}

let answer1 = testFunc(addTwoNum, c: 4, d: 5) // answer1 = 9
let answer2 = testFunc(mulTwoNum, c: 4, d: 5) // answer2 = 20

func addTwoNum(a:Int,b:Int) -> Int {

return a+b

}

func mulTwoNum(a:Int,b:Int) -> Int {

return a*b

}

func testFunc(adderFunc:(Int,Int)->Int,c:Int,d:Int) -> Int {

let answer = adderFunc(c,d)

return answer

}

let answer1 = testFunc(addTwoNum, c: 4, d: 5) // answer1 = 9

let answer2 = testFunc(mulTwoNum, c: 4, d: 5) // answer2 = 20

So, in above program we have to similar type of functions. addTwoNum and mulTwoNum. Another function is testFunc – that takes two integers and a function as a parameter. Wonderful is that we passed first addTwoNum as parameter and then mulTwoNum and we got both results accordingly.

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