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SOLVED: 100days Challenge: Output between function call via a variable and direct function call are different.

Forums > Swift

@daa  

Why are the results different? Calling this function via a variable produces the predicted output, calling the function directly returns the closure. It is not life-threatening, but maybe it helps me to understand the basic concepts better.

func swingBat() -> () -> Void {
    var swingCount = 0
    return {
        if swingCount >= 3 {
            print("You're out!")
        } else {
            print("Strike \(swingCount + 1)")
        }
        swingCount += 1
    }
}
let swing = swingBat()
swing()
swing()
swing()
swing()
swingBat()
swingBat()
swingBat()
swingBat()

screenshot

   

@daa  

Maybe I figured it out myself.

swing is just a variable that holds a function

swing() calls than actually the assigned function and let it do its processing.

similar:

swingBat() is the function itself (swingBat().self)

to let actually do the functions its work I have to call it like this: swingBat()() – allthough it's a bit strange looking for me it does the job

Bildschirmfoto-2020-04-13-um-14-47-14.png

Maybe this is an explanation that makes some sense.

Any ideas?

Thank you.

   

swingBat() is the function itself (swingBat().self)

Not quite. It returns a function that you can then call by appending an additional set of (). So by calling swingBat() you get back a function; by calling swingBat()() you get back a function and then immediately call that function.

   

@daa  

Now I see more clearly. Thank you @roosterboy.

   

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