What is the easiest way to generate random integers within a range in Swift?

Question

The method I've devised so far is this:

func randRange (lower : Int , upper : Int) -> Int {     let difference = upper - lower     return Int(Float(rand())/Float(RAND_MAX) * Float(difference + 1)) + lower } 

This generates random integers between lower and upper inclusive.

Answer 1

Here's a somewhat lighter version of it:

func randRange (lower: Int , upper: Int) -> Int {     return lower + Int(arc4random_uniform(UInt32(upper - lower + 1))) } 

This can be simplified even further if you decide this function works with unsigned values only:

func randRange (lower: UInt32 , upper: UInt32) -> UInt32 {     return lower + arc4random_uniform(upper - lower + 1) } 

Or, following Anton's (+1 for you) excellent idea of using a range as parameter:

func random(range: Range<UInt32>) -> UInt32 {     return range.startIndex + arc4random_uniform(range.endIndex - range.startIndex + 1) }