For example, if you want to double a number in place – i.e., change the value directly rather than returning a new one – you might write a function like this:

In this sentence Paul said i.e but ı dont know what does it mean. Can anyone explain?

He means that you could write a function like this to double a number and return the value...

var myNumber = 5

func doubleAndReturn(number: Int) -> Int {
    return number * 2
}

myNumber = doubleAndReturn(myNumber)

print(myNumber)

(Notice that this function returns an Int, and we set myNumber equal to the thing that is returned when we call the function.)

Or your could write a function like this to double the number in place...

var myNumber = 5

func doubleInPlace(number: inout Int) {
    number *= 2
}

doubleInPlace(myNumber)

print(myNumber)

(Notice here that this function does not return anything, and we do not need to set our variable equal to the return value of the function. We simply call the function, and the variable's value is changed inside of the function when the function is called.)

Howdy,

To build on FlyOstrich's idea the original sentence may be read as...

For example, if you want to double a number in place – that is to say, change the value directly rather than returning a new one – you might write a function like this:

I'm assuming Paul then writes a function in the video.