I need a hand...

The challenge never asks you to create a new constant named 'greeting'. The solution should look like this after all 3 tasks of the challenge:

func greeting(person: String) {
    println("Hello \(person)")
}
greeting("Tom")

The goal of this example is to create function because it makes life easier. For example : you could have just create variables and assign to them random values and then use println() method to display back to the user (see code below )

            var person : String = " John "
             println("Hello \(person) ")

However this method is not really efficient . Lets say you had to input 50+ names it will take you sometime. Therefore you could create a function that takes one parameter and return or display using the println() whatever you assign to it , and this will save the day !!! :)

                  / / create the function using keyword func 
                func greeting(person: String) {
                  println("Hello \(person)")
               } 

         greeting("Tom")     // you call back  the function 

Hope that helps ...