FAQs

1. Q: Can we assume that there are no duplicate values in each of the left and right "sets"?
   A: Yes. As two examples, you'll never see a file like this,

   A:1
   A:2
   

   or this:

   A:1
   B:1
   

2. Q: My xfield.rb has more bugs than macOS! What sort of debugging tools has Ruby got?
   A: For some simple things, see Ruby Debugging.
3. Q: What's the printf format I should use to get a line like 4 correct in 7 guesses = 57.1%?
   A: printf("%d correct in %d guesses = %.1f%%\n", ...) Note that the doubled percent sign produces a single percent sign of output.

Clarifications

None yet!

Corrections

1. The write-up doesn't specify how to handle the case of no guesses, which occurs if the user enters "/u" immediately. Do this:

   $ ruby flash.rb a5/hexlets.fc 
   B? /u
   Done!
   
   No guesses!
   
   Never answered:
   A: 10
   B: 11
   C: 12
   D: 13
   E: 14
   F: 15
   

Typos (corrected in a5.html)

1. The "a5" at the end of the following line was spurious:

   $ ruby xfield.rb -s. A 1 B C 2 D 3 E  < a5/xf.2a5