# Inheritance question **URL:** \ **Category:** Ruby\ **Created:** [March 17, 2007, 6:50pm UTC](https://www.ruby-forum.com/t/inheritance-question/89136 "2007-03-17T18:50:35Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![ckonrad](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/a4c791/32.png) [@ckonrad](https://www.ruby-forum.com/u/ckonrad)\ **Post date:** [March 17, 2007, 6:50pm UTC](https://www.ruby-forum.com/t/inheritance-question/89136/1 "2007-03-17T18:50:35Z")
I am trying to figure out how inheritance works using the super method. With the sample code below i get the error that i dont have enough arguments for the constructor i dont understand why i am getting that error. class Animal def initialize(color, age) @color = color @age = age end attr\_accessor :color attr\_accessor :age end class Dog \< Animal def initialize(color, age, sound) super(color) super(age) @sound = sound end attr\_accessor :sound end dog = Dog.new(“red”, 25, “Bark”) puts “The new dog is #{dog.color}” puts “The age of the dog is #{dog.age}” puts “The new dog says #{dog.sound}” ---
**Author:** ![ckonrad](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/a4c791/32.png) [@ckonrad](https://www.ruby-forum.com/u/ckonrad)\ **Post date:** [March 17, 2007, 6:57pm UTC](https://www.ruby-forum.com/t/inheritance-question/89136/2 "2007-03-17T18:57:40Z")
On 3/17/07, Corey K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > I am trying to figure out how inheritance works using the super method. > With the sample code below i get the error that i dont have enough > arguments for the constructor i dont understand why i am getting that > error. > class Dog \< Animal > def initialize(color, age, sound) > super(color,age) > @sound = sound > end Animals initialize method has two arguments. – Rick DeNatale My blog on Ruby [http://talklikeaduck.denhaven2.com/](http://talklikeaduck.denhaven2.com/) ---
**Author:** ![ckonrad](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/a4c791/32.png) [@ckonrad](https://www.ruby-forum.com/u/ckonrad)\ **Post date:** [March 17, 2007, 7:01pm UTC](https://www.ruby-forum.com/t/inheritance-question/89136/3 "2007-03-17T19:01:19Z")
Rick Denatale wrote: > On 3/17/07, Corey K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > I am trying to figure out how inheritance works using the super method. > > With the sample code below i get the error that i dont have enough > > arguments for the constructor i dont understand why i am getting that > > error. > > > class Dog \< Animal > > def initialize(color, age, sound) > > super(color,age) > > @sound = sound > > end > > Animals initialize method has two arguments. > > – > Rick DeNatale > > My blog on Ruby > [http://talklikeaduck.denhaven2.com/](http://talklikeaduck.denhaven2.com/) i Know but i initialized all of them in this statement though I initialized the 2 in the super class and then the 1 in the subclass: dog = Dog.new(“red”, 25, “Bark”) ---
**Author:** ![ckonrad](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/a4c791/32.png) [@ckonrad](https://www.ruby-forum.com/u/ckonrad)\ **Post date:** [March 17, 2007, 7:37pm UTC](https://www.ruby-forum.com/t/inheritance-question/89136/4 "2007-03-17T19:37:48Z")
Le samedi 17 mars 2007 18:50, Corey K. a écrit : > I am trying to figure out how inheritance works using the super method. > With the sample code below i get the error that i dont have enough > arguments for the constructor i dont understand why i am getting that > error. > […] Hi Corey, I have read the questions you posted the last few days, and I would like to give you a general counsel. It looks like you don’t take care of the output when an exception is raised. Though, the informations displayed when an error occurs are very useful, and if you had paid attention to it, you would have found your error immediatly. For your particular problem, you can see this output : /tmp/animal.rb:13:in `initialize': wrong number of arguments (1 for 2) (ArgumentError) from /tmp/animal.rb:13:in`initialize’ from /tmp/animal.rb:21:in `new’ from /tmp/animal.rb:21 If you don’t already know, the first line means that at line 13 (line 13 is : super(color)) a method was called with 1 argument instead of 2. This is sufficient to start tracking down the error. The other lines represents the call stack, ie the “path” which was followed to reach the exception. And if there is an exception you don’t understand, or that doesn’t help you, then join it with your code in your next message. Happy learning 🙂 ---
**Author:** ![ckonrad](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/a4c791/32.png) [@ckonrad](https://www.ruby-forum.com/u/ckonrad)\ **Post date:** [March 17, 2007, 8:34pm UTC](https://www.ruby-forum.com/t/inheritance-question/89136/5 "2007-03-17T20:34:24Z")
Olivier R. wrote: > Le samedi 17 mars 2007 18:50, Corey K. a écrit : > > > I am trying to figure out how inheritance works using the super method. > > With the sample code below i get the error that i dont have enough > > arguments for the constructor i dont understand why i am getting that > > error. > > […] > > Hi Corey, > > I have read the questions you posted the last few days, and I would like > to > give you a general counsel. It looks like you don’t take care of the > output > when an exception is raised. Though, the informations displayed when an > error > occurs are very useful, and if you had paid attention to it, you would > have > found your error immediatly. > > For your particular problem, you can see this output : > > /tmp/animal.rb:13:in `initialize': wrong number of arguments (1 for 2) (ArgumentError) from /tmp/animal.rb:13:in`initialize’ > from /tmp/animal.rb:21:in `new’ > from /tmp/animal.rb:21 > > If you don’t already know, the first line means that at line 13 (line 13 > is : > super(color)) a method was called with 1 argument instead of 2. This is > sufficient to start tracking down the error. The other lines represents > the > call stack, ie the “path” which was followed to reach the exception. > > And if there is an exception you don’t understand, or that doesn’t help > you, > then join it with your code in your next message. > > Happy learning 🙂 Alright thanks for the information. I knew what the error message meant to some degree i knew it had to do with the number of args in the constructor and i knew what line it was on but i still didnt understand why it was happening because i didnt understand how to use the super method correctly, i looked it up doing a ri super and there was no info that shed light on the issue either so i asked on here. The error message didnt help me out at all i mean if it spit out “Hey corey you need to do this super(color, age) instead of super(color) super(age)” then i would have had no problems understanding that. ---
**Author:** ![ckonrad](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/a4c791/32.png) [@ckonrad](https://www.ruby-forum.com/u/ckonrad)\ **Post date:** [March 17, 2007, 9:44pm UTC](https://www.ruby-forum.com/t/inheritance-question/89136/6 "2007-03-17T21:44:59Z")
On Mar 17, 2007, at 3:34 PM, Corey K. wrote: > i still didnt understand > why it was happening because i didnt understand how to use the super > method correctly, i looked it up doing a ri super and there was no > info > that shed light on the issue either so i asked on here. Your thought to look at ‘ri super’ makes sense. Unfortunately, ‘super’ isn’t actually a method, although it looks like one. It is actually a keyword that is part of the language syntax in the same way that ‘class’ and ‘end’ are in: ``` class Animal end ``` The ‘ri’ tool is only helpful in looking up actual methods and doesn’t really help at all with the underlying language structure and semantics. Other things that look like methods but that you won’t find explained via ‘ri’ are: yield next break return and so on. Best to use the index of the Pickaxe or Ruby Way or some other Ruby reference for these types of things. I wonder if it might make sense to have the standard Ruby documentation include basic information on keywords and incorporate that into the ri/rdoc documentation set. Gary W. ---
**Author:** ![ckonrad](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/a4c791/32.png) [@ckonrad](https://www.ruby-forum.com/u/ckonrad)\ **Post date:** [March 17, 2007, 7:03pm UTC](https://www.ruby-forum.com/t/inheritance-question/89136/7 "2007-03-17T19:03:41Z")
Rick Denatale wrote: > On 3/17/07, Corey K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > I am trying to figure out how inheritance works using the super method. > > With the sample code below i get the error that i dont have enough > > arguments for the constructor i dont understand why i am getting that > > error. > > > class Dog \< Animal > > def initialize(color, age, sound) > > super(color,age) > > @sound = sound > > end > > Animals initialize method has two arguments. > > – > Rick DeNatale > > My blog on Ruby > [http://talklikeaduck.denhaven2.com/](http://talklikeaduck.denhaven2.com/) oh you just use 1 super method for all the args in the super class’s constructor, i was doing super(color) super(age) but its just supposed to be super(color, age) ok thanks ---
**Author:** ![ckonrad](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/a4c791/32.png) [@ckonrad](https://www.ruby-forum.com/u/ckonrad)\ **Post date:** [March 18, 2007, 2:10am UTC](https://www.ruby-forum.com/t/inheritance-question/89136/8 "2007-03-18T02:10:55Z")
> The ‘ri’ tool is only helpful in looking up actual methods and > doesn’t really help at all with the underlying language structure > and semantics. Other things that look like methods but that you > won’t find explained via ‘ri’ are: > > yield > next > break > return > > and so on. Best to use the index of the Pickaxe or Ruby Way or some > other Ruby reference for these types of things. > > I wonder if it might make sense to have the standard Ruby documentation > include basic information on keywords and incorporate that into > the ri/rdoc documentation set. > > Gary W. oh ok thanks i didnt know that either, i am learning alot of stuff today if i keep at this pace for awhile i should be up and running with ruby on rails in no time and then i can figure out what to do with it.