# Array troubles **URL:** \ **Category:** Ruby\ **Created:** [May 25, 2007, 4:31pm UTC](https://www.ruby-forum.com/t/array-troubles/105079 "2007-05-25T16:31:05Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [May 25, 2007, 4:31pm UTC](https://www.ruby-forum.com/t/array-troubles/105079/1 "2007-05-25T16:31:05Z")
I’m converting a Java calculator program I wrote into Ruby–which, just so you know, has been unbelievable with how quickly the language can be learned and implemented and how easy it made programming what had taken months of Java (but that was during school-time so development was, admittedly, very slow)–but I’ve run into a problem. In a term, if you have q/q^2/4/8, it turns into q^-1/.5, but I’m getting q^-10! I’ve narrowed it down to one part of one function: division in Term#simplify. There’s a lot of code involved, so I’ll only post relevant data. I REALLY do think you’ll need any more than this. Also: when I say algebraic calculator, I mean that half the time you’re working with letters (variables), not numbers. Term#simplify > > ``` > > num1 = @items[count-1] > > temp << num1/num2 > > puts 'temp post ' + (temp).to_s > > end > > end > > end > > count += 1 > > end > > puts temp[1] > > temp > > > > ``` > > > > end With q/q^2/4/8 it prints out > > temp pre > > q/q^2 = q^-1 > > temp post q^-1 > > temp pre q^-1 > > 4/8 = 0 > > temp post q^-10 > > 0 Interestingly enough, 4/8=0. I don’t know how the hell that works. Also, when it goes around for the second time to get 4/8, it puts it in the first place in the array (array[0]) and not the next space, which is where I thought this method is supposed to put it. ri must have this wrong too. I don’t think you need to know how I divide variables, but just in case you do: > > # Return the result of this instance and var1. > > > > # Assumes that the two are like. > > > > def /(var) > > Variable.new(self.base, (self.exponent-var.exponent)) > > end A variable is just a string base and integer exponent. PS: I would accept some criticism as long as it’s productive, but I do know that my code is lacking in certain areas (like how it doesn’t check whether or not the variables have like bases), but it is a WIP. ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [May 25, 2007, 4:51pm UTC](https://www.ruby-forum.com/t/array-troubles/105079/2 "2007-05-25T16:51:07Z")
On 25.05.2007 16:26, removed\_email\_address@domain.invalid wrote: > There’s a lot of code involved, so I’ll only post relevant data. I > > > > ``` > > > # You can't do much if the operands aren't of the same class. > > > if num1.class.eql?( num2.class ) > > > puts 'temp pre ' + (temp).to_s > > > # And use the / method of whatever class they are. > > > puts num1.to_s + item + num2.to_s + " = " + > > > (num1/num2).to_s > > > > > > ``` You don’t need all the #to\_s, instead you can do print num1, item, num2, " = ", (num1/num2), “\n” or use printf or puts with string interpolation. > Interestingly enough, 4/8=0. I don’t know how the hell that works. > That’s standard behavior for integer math in programming languages. You > might want to look into mathn / Rational: irb(main):001:0\> 4/8 =\> 0 irb(main):002:0\> require ‘mathn’ =\> true irb(main):003:0\> 4/8 =\> 1/2 irb(main):004:0\> (4/8).class =\> Rational irb(main):005:0\> (4/8).to\_f =\> 0.5 irb(main):006:0\> “%10f” % (4/8) =\> " 0.500000" > > > def /(var) > > > Variable.new(self.base, (self.exponent-var.exponent)) > > > end > > A variable is just a string base and integer exponent. > > PS: I would accept some criticism as long as it’s productive, but I do > know that my code is lacking in certain areas (like how it doesn’t > check whether or not the variables have like bases), but it is a WIP. Hope the math hint gets you started. Kind regards robert ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [May 25, 2007, 5:18pm UTC](https://www.ruby-forum.com/t/array-troubles/105079/3 "2007-05-25T17:18:11Z")
> Hope the math hint gets you started. > > Kind regards > > ``` > robert > > ``` Thanks bundles of bundles! You haven’t solved my main problem (the term array), but this is damn illuminating. Also, it might help me when I’m trying to make this calc with fractions because this already does fractions! The problem will just be making them compatible with variables. ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [May 25, 2007, 6:22pm UTC](https://www.ruby-forum.com/t/array-troubles/105079/4 "2007-05-25T18:22:19Z")
removed\_email\_address@domain.invalid wrote: > In a term, if you have q/q^2/4/8, it turns into q^-1/.5, but I’m > getting q^-10! Hmm… shouldn’t that be q^-1/32 ?