I just started to teach myself ruby as a first language from Chris
Pines''s book. There is a exercise to write a program that will
translate arabic numbers to old style roman numbers.
I have completed the exercise and my code is works but only if I type
in numbers that are not divisible by 5. As soon I type in a number
divisible by 5 I get the following error: No implicit conversion from
nil to integer (Type error)
I completely stuck.
I would be really grateful if someone could look at my code and
explain what am I doing wrong.
puts ''Please type in a number that you would like to be
translated''
puts ''to old style Roman number:''
def romnum leftover
var_i = ''I''
var_v = ''V''
var_x = ''X''
var_l = ''L''
var_c = ''C''
var_d = ''D''
var_m = ''M''
leftover = ''''
leftover = gets.chomp
numb_m = leftover.to_i / 1000
leftover = leftover.to_i % 1000
if leftover != 0
numb_d = leftover / 500
leftover = leftover % 500
if leftover != 0
numb_c = leftover / 100
leftover = leftover % 100
if leftover != 0
numb_l = leftover / 50
leftover = leftover % 50
if leftover != 0
numb_x = leftover /10
leftover = leftover % 10
if leftover != 0
numb_v = leftover / 5
leftover = leftover % 5
if leftover != 0
numb_i = leftover /1
leftover = 0
end
end
end
end
end
end
puts var_m * numb_m + var_d * numb_d + var_c * numb_c + var_l *
numb_l + var_x * numb_x + var_v * numb_v + var_i * numb_i
end
romnum 5
--
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.
Ahmy Yulrizka On Wed, Jan 11, 2012 at 1:43 AM, Loren <loren.boros-PkbjNfxxIARBDgjK7y7TUQ@public.gmane.org> wrote:> def romnum leftover > var_i = ''I'' > var_v = ''V'' > var_x = ''X'' > var_l = ''L'' > var_c = ''C'' > var_d = ''D'' > var_m = ''M'' > > leftover = '''' > > leftover = gets.chomp > > numb_m = leftover.to_i / 1000 > leftover = leftover.to_i % 1000 > > if leftover != 0 > numb_d = leftover / 500 > leftover = leftover % 500 > > if leftover != 0 > numb_c = leftover / 100 > leftover = leftover % 100 > > if leftover != 0 > numb_l = leftover / 50 > leftover = leftover % 50 > > if leftover != 0 > numb_x = leftover /10 > leftover = leftover % 10 > > if leftover != 0 > numb_v = leftover / 5 > leftover = leftover % 5 ># at this line, leftover = 0> > * if leftover != 0 > numb_i = leftover /1 # this line will neger get > call, so numb_i is nil > leftover = 0 > end* > end > end > end > end > end > > > puts var_m * numb_m + var_d * numb_d + var_c * numb_c + var_l * > numb_l + var_x * numb_x + var_v * numb_v + *var_i * numb_i* >this line interpret as *var_i * nil* hence that error simple solution is change it to : var_i * (numb_i || 0) that line actually mean : var_i * numb_i if numb_i is not nil else var_i * 0> > end >-- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On 11 January 2012 11:07, Ahmy Yulrizka <ahmy135-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> > Ahmy Yulrizka > > > On Wed, Jan 11, 2012 at 1:43 AM, Loren <loren.boros-PkbjNfxxIARBDgjK7y7TUQ@public.gmane.org> wrote: >> >> ... >> puts var_m * numb_m + var_d * numb_d + var_c * numb_c + var_l * >> numb_l + var_x * numb_x + var_v * numb_v + var_i * numb_i > > > this line interpret as var_i * nil > hence that error > > simple solution is > > change it to : > > var_i * (numb_i || 0) > > that line actually mean : > > var_i * numb_i if numb_i is not nil > else var_i * 0Also have a look at the Rails Guide on debugging, that will show you how to use ruby-debug to break into your code and inspect data, which will help when you have similar issues again. Colin -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
Thank you. I will take a look at it. On Jan 11, 3:04 pm, Colin Law <clan...-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org> wrote:> On 11 January 2012 11:07, Ahmy Yulrizka <ahmy...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > > > > > > > > > > > Ahmy Yulrizka > > > On Wed, Jan 11, 2012 at 1:43 AM, Loren <loren.bo...-PkbjNfxxIARBDgjK7y7TUQ@public.gmane.org> wrote: > > >> ... > >> puts var_m * numb_m + var_d * numb_d + var_c * numb_c + var_l * > >> numb_l + var_x * numb_x + var_v * numb_v + var_i * numb_i > > > this line interpret as var_i * nil > > hence that error > > > simple solution is > > > change it to : > > > var_i * (numb_i || 0) > > > that line actually mean : > > > var_i * numb_i if numb_i is not nil > > else var_i * 0 > > Also have a look at the Rails Guide on debugging, that will show you > how to use ruby-debug to break into your code and inspect data, which > will help when you have similar issues again. > > Colin-- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On Wed, Jan 11, 2012 at 06:07, Ahmy Yulrizka <ahmy135-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> simple solution is > > change it to : > > var_i * (numb_i || 0)Even simpler solution is to initialize the variable first. But with that approach, you should do them all -- the current solution will barf on the first digit past the one that the number is a multiple of. (That is, if you feed it 30, it will barf due to var_v being nil; if you feed it 150, it''ll barf due to num_x being nil, etc.) Another one would be to just output the needed digits immediately, rather than stashing the number of them and outputting them later. -Dave -- Dave Aronson, President, Dave Aronson Software Engineering and Training Ruby on Rails Freelancing (Northern Virginia, Washington DC, or Remote) DaveAronson.com, Codosaur.us, Dare2XL.com, & RecruitingRants.com (NEW!) Specialization is for insects. (Heinlein) - Have Pun, Will Babble! (me) -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.