I have a character shooting and I want him to only shoot when user is touching the screen, I keep getting this error "'GameScene' does not have a member named 'stimer'
here is the code

```
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
    /* Called when a touch begins */

    for touch: AnyObject in touches {
        var stimer = NSTimer.scheduledTimerWithTimeInterval(0.5, target: self, selector: Selector("spawnShot"), userInfo: nil, repeats: true)
        let location = touch.locationInNode(self)
        player.position.x = location.x

    }
}
   override func touchesEnded(touches: Set<NSObject>, withEvent: UIEvent){
    for touch: AnyObject in touches{
        if self.stimer.valid{

            self.timer.invalidate()
            self.timer = nil
        }

    }
}

```