Classical Bowling kata using Java and JUnit 5.
The task is to write a score calculator. The input is a string of characters and the output is integer points. The characters are single digits numbers 1.9, " ", "-", "/" and "X". The latter represents no roll, zero, spare and strike, respectively. The calculator shall handle partial inputs.
See below for explanation of those terms.
At the end, there are some suggestions for testing.
There are currently two catalogs, java and python. These give you the opportunity to practice in different languages.
Wikipedia: https://en.wikipedia.org/wiki/Ten-pin_bowling#Scoring
The most difficult part of bowling scoring to comprehend is when a strike or spare is scored, as the score on the scorecard does not get updated immediately.
A game consists of ten frames, which start with a full rack of ten pins. In each frame, you have two deliveries of your ball, in which to knock down as many of the ten pins as you can.
If you knock down all the pins on your first ball, it is called a strike. The score doesn't get added on straight away because for a strike, you get the value of your next two balls as a bonus.
For example, if you score a strike in the first frame, then a 7 and 1 in the second frame, you would score 18 (10+7+1) for the first frame, and 8 for the second frame, making a total of 26 after two frames.
If you knock down some of the pins on the first ball, and knocked down the remainder of the pins in the second ball, it is known as a spare. Again, the score does not get added on straight away because for a spare, you get the value of your next ball as a bonus.
For example, if you score a spare in the first frame, say a 6 and a 4, then got an 8 and a 1 in the second frame, you would score 18 (6+4+8) for the first frame, and 9 for the second frame, making a total of 27 after two frames.
When it comes to the final frame, it is slightly different. In the final frame, you get bonus balls if you strike or spare, to a maximum of three deliveries.
If you strike in the first delivery you have the opportunity to strike in the remaining two and have three deliveries in total. If you scored strikes in each of your final three deliveries, the score for the final frame would be 30 (10+10+10).
If you spare the final frame, you get the third delivery as a bonus. So, a spare, 9 and 1, followed by a strike would equal 20 (9+1+10).
The syntax is: each frame is two characters, except the last which three.
Remember that the final frame is different.
"X X X X X X X X X XXX" (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
"45" = 1 Frame 4 + 5 = 9
"3/" = 1 Frame with spare but no following = 0
"3/2" = 1 Frame with spare and a following roll = 10 + 2 = 12
"X " = 1 Frame with strike but no following = 0
"X 2" = 1 Frame with strike and a following roll = 0
"X 23" = 2 Frame with strike in first = 10 + 2 + 3 + 2 + 3 = 20
The maximum points you can reach is 300. The minimum is 0.
There are never more than 10 frames but the final frame (10th) may have three rolls.