BowlingSecondPractice.Frame.SecondToNextBall C# (CSharp) 메소드

        private int SecondToNextBall()
        {
            var nextIsNotLast = NextFrame.NextFrame != null;
            if (NextFrame.IsStrike() && nextIsNotLast)
            {
                return NextFrame.NextFrame.FirstBall;
            }
            return NextFrame.SecondBall;
        }