You can declare a function with the func keyword.
Functions organizes code into reusable chunks that take input parameters and return results.
The following code shows an example of a function that returns the string "Hello World."
func myFunction() -> String{
return "Hello World"
}
let s = myFunction();
println(s)
//Calling Functions Directly
println(myFunction())
In the code above, the function declaration starts with the func keyword
followed by the name of the function.
The following code shows a function that just writes out the log without returning a value.
func myFunction() {
println("Printing myFunction() function")
return
}
myFunction()
To declare a function with parameters, you include the name of the parameter and the data type of the parameter.
func averageScore(scores:[Float]) -> Float{
var total:Float = 0
var count:Float = 0
for score in scores{
total+=score
count++
}
return total / count
}
let result = averageScore([0, 9, 4, 6, 7, 5, 3, 9])
When functions have more than one parameter, you include them in a comma-separated list.
func printStuff (this:String, that:String){
println("\(this) \(that)!")
return
}
printStuff("Hello", "World")
You can code functions within other functions.
Nesting functions can organize and reuse our code while limiting the scope of functions to the parent function.
func myFunction(){
func calculate(scores:[Int]) -> Float?{
if scores.count > 0 {
var total:Int = 0
var count:Int = 0
for score in scores{
total+=score
count++
}
return (Float)(total / count)
}else {
return nil
}
}
func printReport(testName:String, scores:[Int]){
if let a = calculate(scores){
println("\(testName) Test Results")
println(" The average score is \(a)")
}
}
printReport("Math", [9, 4, 2, 6, 5, 5, 3, 9])
printReport("Java", [3, 7, 2, 5])
}
myFunction()