http://codingdojo.org/kata/Bowling/
Create a program, which, given a valid sequence of rolls for one line of American Ten-Pin Bowling, produces the total score for the game. Here are some things that the program will not do:
Check for valid rolls. Check for correct number of rolls and frames. Provide scores for intermediate frames.
Each game, or “line” of bowling, includes ten turns, or “frames” for the bowler. In each frame, the bowler gets up to two tries to knock down all the pins. If in two tries, they fail to knock them all down, there score for that frame is the total number of pins knocked down in his two tries.
If in two tries they knocks them all down, this is called a “spare” and their score for the frame is ten plus the number of pins knocked down during their next turn.
If on their first try in the frame they knock down all the pins, this is called a “strike”. Their turn is over, and their score for the frame is ten plus the simple total of the pins knocked down in his next two rolls.
If they get a spare or strike in the last (tenth) frame, they gets to throw one or two more bonus balls, respectively. These bonus throws are taken as part of the same turn. If the bonus throws knock down all the pins, the process does not repeat: the bonus throws are only used to calculate the score of the final frame.
The game score is the total of all frame scores.
What makes this game interesting to score is the lookahead in the scoring for strike and spare. At the time we throw a strike or spare, we cannot calculate the frame score: we have to wait one or two frames to find out what the bonus is.
(When scoring “X” indicates a strike, “/” indicates a spare, “-” indicates a miss)
X X X X X X X X X X X X (12 rolls: 12 strikes) = 10 frames * 30 points = 300
9- 9- 9- 9- 9- 9- 9- 9- 9- 9- (20 rolls: 10 pairs of 9 and miss) = 10 frames * 9 points = 90
5/ 5/ 5/ 5/ 5/ 5/ 5/ 5/ 5/ 5/5 (21 rolls: 10 pairs of 5 and spare, with a final 5) = 10 frames * 15 points = 150