From: Dark Ambient <sambient@...>
Date: 2006-06-27T02:27:48+09:00
Subject: Re: Stumped:beginners question

Alright, if there are any people remaining that have some patience to
repeat I'm running into the same problem again. And for now I really
want to stick to while,because now it's a real sticking point for me.
If I do nothing else in Ruby, mastering the while statement is a
must.:)

So here I've created a method.  See inline for why I think it should work.

#sort is the parameter for the alpha method
def alpha sort

#setting up my arrays
  s_words = []
  u_words = []

#assign a blank string to sort to start things off
  sort = ' '

# what I'm trying to say here is that if sort remains empty continue the loop
while sort == ' '
# to prompt the user to enter something I've added the puts statement
  puts 'Please enter a word to be sorted'
#Now I'll assign sort to whatever the user inputs.
  sort = gets.chomp.downcase
#Now I want to put the string into the array.
  u_words.push['sort']
#I haven't thought it completely through but I'll probably want to
give the user a
#surrender word to stop the loop.  Still I think at this point it
should loop at least
#once.  Sadly, it does not, so either I'm thick or this is a hard
concept for me.  #Polymorphism seems easier to grasp right now
  end
end

TIA
Stuart
On 6/26/06, Robert Dober <robert.dober@gmail.com> wrote:
>
>
>
> On 6/26/06, Dark Ambient <sambient@gmail.com> wrote:
> > Robert,
> >
> > Thank you for a great explanation. I have a question or two and might
> > have some more later :).  The program is an assignment in a book
> > "learn to program" which uses Ruby but is pretty much for beginners.
> > While I've seen some of the of the other condition testers, (when, do,
> > case, etc) the author sticks to the real basics, while, if, else and
> > elsif.   The author did write the program out, somewhat verbose and
> > asked that it be re-written.  Suprisingly, he said while he DOES NOT
> > like to use "return", he might be forgiving if it was used in the
>
>
> This is a very extreme point of view, like when I learnt Pascal in
> university.
>
> > re-write.  Admitedly, your code is far cleaner and more to Matz's
> > style of Ruby being almost like pseudo-code.
> > So, question 1 - "loop do" seems like a great alternative to "while"
>
>
> No loop do ... end  or loop { } is the aequivaelent to
>      while true do    or while(true){ }
> it is an endless loop.
>
> > but could it be subsituted all the time when a loop is required ?  or
> > are there times when while has some unique ways of doing things ?
> >
> > You wrote:
> > "surprisingly the example you chose, which is needed> about everywhere is
> > not the easiest to implement".
>
>
> > Question 2 - I'm not sure how to take this statement.  To me in the
> > context of programming it seems like a pretty basic function
> > regardless of how one may master it but interested in why you chose
> > the words you did ?
>
>
> Because of the need to return from the middle of the loop
>
> > Look forward to your responses.
> >
> > Thank you again!
> > Stuart
>
>
> H''s been a pleasure.
> Cheers
> Robert
>
> > On 6/26/06, Robert Dober <robert.dober@gmail.com> wrote:
> > > Hi ambient
> > >
> > > I will answer this off-list not because it was a bad thing of you to
> answer
> > > on list but just because you were unlucky with the anwsers ;)
> > >
> > > First I will give you the code
> > > def ask question
> > >      loop do  ### this loops forever, and that's what we need because of
> the
> > > loosers ;)
> > >
> > >          puts question
> > >          case gets.chomp.downcase
> > >              when "yes"
> > >                 return true
> > >              when "no"
> > >                 return false
> > >              else
> > >                 puts "Please kindly reply with \"yes\" or \"no\"
> > >         end
> > >     end
> > > end
> > >
> > > Now some explanations, the most important trick is to write your code as
> > > simple as possible, surprisingly the example you chose, which is needed
> > > about everywhere is
> > > not the easiest to implement, but local exits (in our case the "return"
> can
> > > be very helpful).
> > >
> > > So what did you want to do?
> > > Ask the user a question
> > > get a reply
> > > return true or false if the reply is syntactically correct
> > > Insult the looser ;) in any other case and do it again
> > >
> > > As there is no looping construct which tests the looping condition after
> the
> > > first run of the loop body it is *normal* that your code gut clumpsy.
> The
> > > endless
> > > loop do
> > > end
> > > or
> > > loop {
> > > }
> > >
> > > often helps to write clearer code, do not forget to break or return from
> > > these loops though!!!
> > >
> > > In our case we want the method to return true or false anyway as soon as
> the
> > > input
> > > is correct, so we kill to birds with one stone.
> > >
> > > The pseudo code above can be translated as follows
> > >
> > > loop do   #### preparing for the potential need to reanswer the question
> ;)
> > >      puts question
> > >      case gets.chomp.downcase  ### examine the reply
> > >         ### return true or false if the code is synt. correct
> > >          when "yes"  ### greatinput is correct we return the
> corresponding
> > > value
> > >              return true  ### returning from the method gets us out of
> the
> > > loop to :))
> > >          when "no"  ### as above
> > >              return false
> > >         else ### Now we get to the insult part and loop back to the
> question
> > >             puts "Please kindly reply with \"yes\" or \"no\""
> > >     end # case
> > > end # loop
> > >
> > > Feel free 2 ask any more questions
> > > Cheers
> > > Robert
> > >
> >
>
>
>
>
> --
> Deux choses sont infinies : l'univers et la b�tise humaine ; en ce qui
> concerne l'univers, je n'en ai pas acquis la certitude absolue.
>
> - Albert Einstein