jeffersonsouza.rb

# This class solves the polynomial problem on the RPCFN #4
# Created by: Jefferson Mariano de Souza
# E-mail: jefmsouza@gmail.com

class Polynomial
  def initialize (aArray)
    @array = aArray
    
    # raises exception if there are less than 2 items in the array
    if @array.size == 1
      raise ArgumentError.new("Need at least 2 coefficients")
    end
  end

  @ prints the string with the polynomial
  def to_s
    if all_zero?
      puts "0"
      exit
    end
    
    text = String.new
    amount = @array.size # stores the amount to guide the exponents

    #iteration
    for item in @array
      (amount == @array.size)?(item>0?sig="":sig="-"):(item>0?sig="+":sig="-")
      if amount > 2 and item != 0
        text << "#{sig}#{item.abs==1?"":item.abs}x^#{amount - 1}"
      elsif amount == 2 and item != 0
        text << "#{sig}#{item.abs==1?"":item.abs}x"
      elsif amount == 1 and item != 0
        text << "#{sig}#{item.abs}"
      end

      amount -= 1
    end

    puts text
  end
  
  # checks if all the items in the array are zeroed
  def all_zero?
    c_zero = 0
    for item in @array
      if item == 0
        c_zero += 1 
      end
    end
    
    (c_zero==@array.size)?true:false
  end
end