From: "David A. Black" <dblack@...>
Date: 2007-11-08T09:13:25+09:00
Subject: Re: alternate to case; generating a list of sub-classes

Hi --

On Thu, 8 Nov 2007, Thufir wrote:

> The below uses pseudo-random number generation to populate an array
> with various monsters, all inherit from Creature.  Can a list of
> classes which inherit from Creature be generated automagically?  There
> must be a better technique to fill the array then the case
> statement...
>
>
> C:\code>
> C:\code>
> C:\code>type Driver.rb
> require 'ArrayOfCreatures'
>
> require 'Creature'
> require 'AssistantViceTentacleAndOmbudsman'
> require 'Dragon'
> require 'DwarvenAngel'
> require 'TeethDeer'
>
>
>
> puts "\nquantity of creatures:"
> numOfCreatures = gets.chomp.to_i
>
>
> someCreatures = ArrayOfCreatures.new
>
>
> 0.upto(numOfCreatures) do |i|
>
>        creatureType = Kernel.rand(4)
>
>        case creatureType
>        when 0
>                someCreatures[i]=AssistantViceTentacleAndOmbudsman.new
>        when 1
>                someCreatures[i]=Dragon.new
>        when 2
>                someCreatures[i]=DwarvenAngel.new
>        when 3
>                someCreatures[i]=TeethDeer.new
>        end
> end
>
> someCreatures.toString

Here's one possibility (untested):

   creatures = ArrayOfCreatures.new
   creature_classes = [AssistantViceTentacleAndOmbudsman, Dragon,
                       DwarvenAngel, TeethDeer]

   puts "\nquantity of creatures:"
   num_of_creatures = gets.to_i

   num_of_creatures.times do |i|
      creatures[i] = creature_classes[rand(4)].new
   end


David

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