Reinvention of array list.

MyArrayList.rb

class MyArrayList

  def initialize n
    if n<0 then
      raise "size should be more than 0";
    end
    @size=n
    @next_index=0
    @innerArray=Array.new @size
  end

  def add element

    if @next_index>@size-1 then
      @size*=2
      extendedAry = Array.new @size
      @innerArray.each_with_index do |val,i|
        extendedAry[i]=val
      end
      @innerArray=extendedAry
    end

    @innerArray[@next_index]=element
    @next_index+=1

  end

  def get n
    if n>=@next_index then
      return nil
    else
      return @innerArray[n]
    end
  end

  def to_s
    result = ""
    result+="current:"+@next_index.to_s
    result+=", size:"[email protected]_s
    result+=", "[email protected]_s
    return result
  end

end

list = MyArrayList.new 2

17.times do |i|
  list.add i
end

p list.to_s