Assign first user touch to variable

I am trying to enable touch on pieces of a sliding tile puzzle so they can each move around the screen.

I want to assign the user's first tap on the screen to

var tapCen = CGPoint();

var left = CGPoint();

var right = CGPoint();

var top = CGPoint();

var bottom = CGPoint();



override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?)

{

    let allTouches = event?.allTouches()

    let myTouch = allTouches?.first



    if myTouch!.view != self.view

    {

        tapCen = myTouch!.view!.center



    }

}