Simple Script Help (New to Ruby)


#1

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

    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.

Thanks in advance!

Warm regards,
Jordan M.
Vivio Technologies


#2
    elseif theNumber = theGuess

I guess you mean == here, not =.

Best, Ulrich


#3

Jordan M. wrote:

   end
   print "The Result: "
   print theNumber
   print "\n"

end

(there is no elseif kayword but elsif)

It seems to be working for me. You could replace the if/elsif statements
with case statement

case
when theNumber < theGuess
# blah
when theNumber > theGuess
# blah
else
# blah
end

lopex


#4

Jordan M. removed_email_address@domain.invalid writes:

   elseif theNumber > theGuess
           theResult = 2
   elseif theNumber = theGuess

elseif is not Ruby… try elsif instead.

furthermore, equality is “==”, not “=”. Here, you assigns theGuess to
theNumber. This assignment return the value of theGuess, hence always
“true”.

and here’s my output when I run it:

Strange. If i try to run your script, i get a :

bla.rb:17: undefined method `elseif’ for main:Object (NoMethodError)

That’s not the case for you ?


#5

oops it seems I missed this (theNumber = theGuess)

lopex


#6

Eric J. wrote:

Strange. If i try to run your script, i get a :

bla.rb:17: undefined method `elseif’ for main:Object (NoMethodError)

That’s not the case for you ?

No, it was not the case, but that might have been helpful!

ruby --version
ruby 1.8.2 (2004-12-25) [i586-linux]

I’m downloading 1.8.4 as I write this. We’ll see if that doesn’t give me
better error messages.

Thanks to all for your support and suggestions! Changing the “elseif” to
“elsif” did the trick. The script now works as intended. I agree with a
lot of your suggestions about equality (==), and using case instead of
if. When programming for clients I make a point to use the most
efficient and correct code as possible, but I’m just playing with this
at the moment. :wink:

Thanks again. It’s nice to have a friendly place to turn to when you
have questions!

Warm regards,
Jordan M.
Vivio Technologies


#7

On 3/4/06, Jordan M. removed_email_address@domain.invalid wrote:

set the default result

    # 1 = number is lower
    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

#8

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

Here is my little script:
theGuess = gets.to_i
theResult = 3

    print "The Result: "
    print theNumber

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 S. removed_email_address@domain.invalid
http://www.stok.ca/~mike/

The “`Stok’ disclaimers” apply.