From: Alex Gutteridge <alexg@...>
Date: 2007-10-02T15:06:00+09:00
Subject: Re: instance variable/ I'm lost

On 2 Oct 2007, at 13:14, Erik Boling wrote:

> . You can
>> just access the @correct variable directly as Bob wrote:
>>
>> @correct = @correct + 1
> Sorry i dont see where, bob wrote that =|.

It is in the first example he gave in his first reply.

> ok i understand everyones ways of going about this except bobs ways of
> using parameters and returned values is messing me up a bit. So  
> heres my
> finished product, if anyone sees anything usless or somthing im doing
> wrong, please let me know :)
>
> puts 'How many problems do you want to solve?'
> problems = gets.chomp
>
> 5.downto(1) do |x|
>   puts "The test will beging #{x} in seconds! "
>   sleep 1
> end
> puts 'Start!'
> def correct=(correct)
>     @correct = correct
>     end
>
>   def correct
>    @correct
>    end
> @correct = 0
>  def multiply
> multiple2 = rand(11)
> multiple1 = rand(11)
>   answer = multiple1 * multiple2
> puts 'what is ' + multiple1.to_s + ' * ' + multiple2.to_s + ' ?'
>   answerp = gets.chomp
>   if answer.to_s == answerp.to_s
>     puts "good job"
>     @correct = @correct + 1
>   else puts "You fail!"
>   end
> end
>
> problems.to_i.times do multiply
> end
>
> puts correct.to_i

You still have two methods defined which do (almost) nothing now. You  
call one of them on the final line, but it isn't necessary because it  
just returns @correct. Apart from that it is OK, I would rearrange  
the various to_i and to_s methods and a few other bits to make it  
(IMO) a bit neater and Ruby-ish:

puts 'How many problems do you want to solve?'
problems = gets.chomp.to_i

5.downto(1) do |x|
   puts "The test will begin in #{x} seconds!"
   sleep 1
end

puts 'Start!'

@correct = 0

def multiply
   multiple2 = rand(11)
   multiple1 = rand(11)
   answer = multiple1 * multiple2
   puts "What is #{multiple1} * #{multiple2} ?"
   answerp = gets.chomp.to_i
   if answer == answerp
     puts "Good job"
     @correct = @correct + 1
   else
     puts "You fail!"
   end
end

problems.times do
   multiply
end

puts @correct

Again though, I wouldn't use instance variables in this case, but  
something like this which is slightly longer, but a bit clearer (for  
me anyway):

puts 'How many problems do you want to solve?'
problems = gets.chomp.to_i

5.downto(1) do |x|
   puts "The test will begin in #{x} seconds!"
   sleep 1
end

puts 'Start!'

def problem_answered?
   multiple2 = rand(11)
   multiple1 = rand(11)
   answer = multiple1 * multiple2
   puts "What is #{multiple1} * #{multiple2} ?"
   answerp = gets.chomp.to_i
   if answer == answerp
     puts "Good job"
     return true
   else
     puts "You fail!"
     return false
   end
end

correct = 0

problems.times do
   if problem_answered?
     correct += 1
   end
end

puts correct

Alex Gutteridge

Bioinformatics Center
Kyoto University