polynomial.rb

class Polynomial
  
  def initialize array
  
    if array.length <= 1
      raise ArgumentError.new('Need at least 2 coefficients')
      exit
    else
      
      @return_string = ''
      @iterations = array.length - 1
      array.each do |item|
        
        if @iterations > 1
          @this_iteration = "^#{@iterations}"
        else
          @this_iteration = ''
        end
      
        if item.abs > 0
          if item > 1
            if @return_string.empty?
              @item_string = "#{item}"
            else
              @item_string = "+#{item}"
            end
          elsif item < -1
            @item_string = "#{item}"
          elsif (item == 1)            
            if @return_string.empty?
              @item_string = ''
            else
              @item_string = '+'
            end
          elsif item == -1
            @item_string = '-'
          end
          
          if @iterations > 0
            @item_string = "#{@item_string}x"
          end
          
          @return_string << "#{@item_string}#{@this_iteration}"
          
        end
        @iterations = @iterations - 1
      end
        
      if @return_string.empty?
        @return_string = '0'
      end
    end
  end
  
  def to_s 
    @return_string
  end
end