From: Mike Stok <mike@...>
Date: 2006-03-05T10:28:57+09:00
Subject: Re: Simple Script Help (New to Ruby)


On 4-Mar-06, at 8:00 PM, Bill Guindon wrote:

> On 3/4/06, Jordan Michaels <jordan@viviotech.net> wrote:
>> Hello Ruby Masters!
>>
>> I'm attempting to write a very simple guessing game script in an  
>> effort
>> to expand my knowledge about the Ruby Language. I'm running ruby  
>> on my
>> OpenSuse Linux 10 box at home. I'm typically a web-programmer, but I
>> want to get into something a little more deep.
>>
>> Here is my little script:
>>
>> ----------------
>> # set the default result
>> theResult = 0
>>
>> # create the random number
>> theNumber = rand(10)
>>
>> while theResult != 3
>>         print "Guess my number: "
>>         theGuess = gets.to_i
>>
>>         # return key
>>         # 1 = number is lower
>>         # 2 = number is higher
>>         # 3 = number matched!
>>         if theNumber < theGuess
>>                 theResult = 1
>>         elseif theNumber > theGuess
>>                 theResult = 2
>>         elseif theNumber = theGuess
>>                 theResult = 3
>>         end
>>
>>         case theResult
>>                 when 1
>>                         puts "My number is lower."
>>                 when 2
>>                         puts "My number is higher."
>>                 when 3
>>                         puts "You guessed my number!"
>>         end
>
> This is a good place to use symbols -- if nothing else, you won't need
> the comments explaining the keys:
>
>          if theNumber < theGuess
>                  theResult = :lower
>          elsif theNumber > theGuess
>                  theResult = :higher
>          elsif theNumber = theGuess
>                  theResult = :equal
>          end
>
>          case theResult
>                  when :lower
>                          puts "My number is lower."
>                  when :higher
>                          puts "My number is higher."
>                  when :equal
>                          puts "You guessed my number!"
>          end
>
>
>>         print "The Result: "
>>         print theResult
>>         print "\n"
>>
>>         print "The Guess: "
>>         print theGuess.class
>>         print "+"
>>         print theGuess
>>         print "\n"
>>
>>         print "The Number: "
>>         print theNumber
>>         print "\n"
>> end
>> ----------------
>>
>> and here's my output when I run it:
>>
>> ----------------
>> utdream@dream:~/ruby_scripts> ruby guess_number.rb
>> Guess my number: 1
>> The Result: 0
>> The Guess: Fixnum+1
>> The Number: 3
>> ----------------
>>
>> The result staying at 0 tells me that NONE of my comparisons  
>> worked. Can
>> anyone tell me why? I'm sure this is something simple but any help  
>> would
>> be appreciated.

You could avoid the symbols if you are prepared to understand the <=>  
comparison, a short example might be

the_number = rand(10)

loop do
   print "Guess my number: "
   the_guess = gets or break     # hit eof

   case the_number <=> the_guess.to_i
     when -1
       puts "My number is lower"
     when  1
       puts "My number is higher"
     else
       puts "You guessed my number"
       break
     end
end

It may be interesting to see how you can trap "bad" input and  
generate a useful error message using what comes with Ruby

Mike

-- 

Mike Stok <mike@stok.ca>
http://www.stok.ca/~mike/

The "`Stok' disclaimers" apply.