common-style-ruby

def triangle(a, b, c)
  if a == 0 || b == 0 || c == 0
    raise TriangleError
  end
  if((a+b < c) || (a+c < b) || (b+c < a))
    raise TriangleError
  end
  if a == b && b == c # && a == c 
    :equilateral
  elsif a == b || b == c || c == a
    :isosceles
  else
    :scalene
  end
end