From: Benjamin Thomas <benjamin.thomas81@...>
Date: 2009-03-11T23:18:05+09:00
Subject: return doesn't always exit my method

Hi, I'm new to Ruby and programming in general.
I'm coding a little script to train on multiplication tables but
something's wrong:

If I type 'exit', the function should normally exit, via a return
statement. But this does not always happen and I really can't understand
why. I've been scratching my head for a few hours on that so I'm posting
here hoping somebody will be able to spot my obvious mistake!

I'm trying to apply here the concept of recursion so maybe this is where
I'm messing up.

Thanks for your input,
Ben


#########################################################################
#!/usr/bin/ruby
require 'yaml'

system "clear"
filename = "tested_list.txt"

if File.exist?(filename)
  imported_list = File.read filename
  $tested = YAML::load imported_list
else
  $tested = {}
end

def rand_multi()
  num1 = rand(10)
  num2 = rand(10)
  got_wrong = false
  operation = "#{num1}*#{num2}"
  if $tested[operation].nil?
    puts "creation!"
    $tested[operation] = 0
  elsif $tested[operation] > 1
    puts "need restart"
    rand_multi()       # forces function call again
  end
  puts "iteration #{$tested[operation]}"
  print operation, " = "
  before = Time.now
  time_before = (before.min * 60) + before.sec  # in case I go for a
coffee :)
  answer = gets.chomp
  if answer =~ /exit/
    puts "will exit now"
    return ##### <-- return statement does not always exit method; why??
######
    # exit
  elsif answer =~ /[0-9]+/
    answer = answer.to_i
  else
    puts "Please enter numbers only!"
    rand_multi()
  end
  if answer != num1 * num2
    print ""                             # terminal colors
    puts "inside not equal"
    puts "No! Answer was '#{num1*num2}'"
    print ""
    sleep(1)
    # system "clear"
    got_wrong = true
    $tested[operation] -= 5         # give negative value
    rand_multi()
  elsif answer == num1 * num2
    after = Time.now
    time_after = (after.min * 60) + after.sec
    answer_time = time_after - time_before
    print ""
    puts "inside equal"
    puts "Yes!, you answered in #{answer_time} seconds"
    print ""
    sleep(0.3)
    # system "clear"
    if got_wrong == false
      if answer_time < 3
        $tested[operation] += 1        # give positive value
      else
        $tested[operation] -= 1        # small penalty if answer too
slow
      end
    end
    rand_multi()
  end
end

puts "Multiplications!"
puts "Type 'exit' to exit"
puts "\n\n"

rand_multi()
puts "Bad answers:"
$tested.each_pair {|key, value| puts "#{key} => #{value}" if value < 0}

File.open filename, 'w' do |f|
  f.write $tested.to_yaml
end
###############################################
-- 
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