Continuation of Hacking With Swift 100 Days of Swift

Day 5 - Functions

Functions are a little bit special for swift, first of all return keyword is not required, function keyword gets boiled down to func, and return statements are specified with -> DataType; kind of bonkers if you ask me but hey, gotta get use to it.

In the other hand here we get an interesting concept, "parameter labels", these allow for a function to have an internal and external name for a passed parameter, ex:

func greet(to name: String) -> String { "Hello! \(name)" }; greet(to: "Davmi");

To get rid of the required parameter name when calling a function we can use the discard operator, the same way print() does not require the parameter to be set print(nameOfParameter: "") we can change our greet function like this:

func greet(_ name: String) -> String { "Hello! \(name)" };

And then the function can be called like: greet("Davmi");

Variadic functions are totally different, while on c# with have the params keyworks, on swift we use ... after the param type, so a variadic function would be

func variadicFunc(numbers: Int...)

In swift all parameters are immutable, in order to pass by reference (modify the value of the parameter), you need to add the ampersand symbol &.