Janice Lichtman - Recursion Tracing

[J-C-L]

Recursion Tracing

Thanks for doing some brain yoga. You are now submitting this assignment!

Comprehension Questions

Question	Answer
Did you define all the recursion terms?	Yes
How do you feel about tracing recursive problems? (good, bad, ugly, neutral)	It's fun! I don't always see the tough ones quickly, but I understand the process.
Would you like help/follow up about recursion?	I'd like to see answers to the 'added fun' questions and the writing recursion exercises.

[sudocrystal]

Answers to added fun:

def mystery2(n)
  if n < 0
    return -1 * mystery2(-n)
  elsif n < 10
    return n
  else
    return (n%10) + mystery2(n/10)
  end
end

def mystery5(s)
  if s.length == 0
    return ""
  elsif s[0].match(/[a-zA-Z]/)
    return "*" + mystery5(s[1..-1])
  else
    return s[0] + mystery5(s[1..-1])
  end
end

def mystery6(s)
  if s.length < 2
    return s
  else
    return mystery6(s[1..-1]) + s[0]
  end
end

[sudocrystal]

This looks like it works. I also just posted an alternative solution that is perhaps more readable.

[sudocrystal]

This looks like it works. I did post another solution to consider.

One thing is to figure out if you think I intended mystery5("Hi, there!") to produce "*******" or "**, *****!"

I intended the latter, but didn't specify so you+others assumed and wrote solutions for the former.

[sudocrystal]

+1 my solution too. Though I wrote the base case differently, they are essentially the same. I didn't account for nil though.

[sudocrystal]

Nice job!