swift - Sending Variables with a Segue -

i working on simple ios swift app. app has 2 view controllers , button has been programmed segue other view controller so:

@ibaction func pushme(sender: anyobject) {         self.performseguewithidentifier("changeit", sender: nil) } 

the above works want able save 2 variables current view controller , make them available view controller segueing to. did this:

override func prepareforsegue(segue: uistoryboardsegue, sender: anyobject!) {     if segue.identifier == "changeit" {         var testvar1 = "hello"         var testvar2 = "world"     } } 

in view controller segueing added:

var testvar1:string! var testvar2:string! 

the app works try access testvar1 or testvar2, app crashes. not sure why isn't working intended?

because variables not initialized, omitted destination view controller. use code below

override func prepareforsegue(segue: uistoryboardsegue, sender: anyobject!) {     if segue.identifier == "changeit" {         let dvc = segue.destinationviewcontroller as! yourdestinationviewcontroller         dvc.testvar1 = "hello"         dvc.testvar2 = "world"     } }