Default parameters

The print() function prints something to the screen, but always adds a new line to the end of whatever you printed, so that multiple calls to print() don’t all appear on the same line.

You can change that behavior if you want, so you could use spaces rather than line breaks. Most of the time, though, folks want new lines, so print() has a terminator parameter that uses new line as its default value.

You can give your own parameters a default value just by writing an = after its type followed by the default you want to give it. So, we could write a greet() function that can optionally print nice greetings:

func greet(_ person: String, nicely: Bool = true) {
    if nicely == true {
        print("Hello, \(person)!")
    } else {
        print("Oh no, it's \(person) again...")
    }
}

That can be called in two ways:

greet("Taylor")
greet("Taylor", nicely: false)