complex.rb

class Complex
  def initialize(_re = 0.0, _im = 0.0)
    self.re = _re
    self.im = _im
  end
  
  def +(val)
    Complex.new(self.re + val.re, self.im + val.im)
  end
  
  attr_accessor :re, :im
end

a = Complex.new(2.1, 3.3)
b = Complex.new(1,1.2)

c  = a + b

puts "#{c.re} + #{c.im}i" #==> 3.1 + 4.5i