Functions

So far, we called some Objective-C functions, but we have not defined any yet. Let's see what the Objective-C versions are of the functions we defined in Chapter 2, Building Blocks – Variables, Collections, and Flow Control.

Our most basic function definition didn't take any arguments and didn't return anything. The Objective-C version looks pretty similar to this:

func sayHello() {
    println("Hello World!");
}
sayHello()

void sayHello() {
    NSLog(@"Hello World!");
}
sayHello();

Objective-C functions always start with the type that the function returns instead of the func keyword. In this case, we aren't actually returning anything, so we use the void keyword to indicate that.

Functions that take arguments and return values have more of a disparity between the two languages:

func addInviteeToListIfSpotAvailable
    (
    invitees: [String],
    newInvitee: String
    )
    -> [String]
{
    if invitees.count >= 20 {
        return invitees
    }
    return invitees + [newInvitee...