Contents

class Integer
  def n_gonal?(n)
    raise ArgumentError unless n.is_a?(Integer) and n >= 3
    return true if zero?
    x = (Math.sqrt((8*n - 16)*self + (n-4)**2) + n - 4) / (2*n - 4)
    x == x.to_i
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
numb-0.21.0	lib/numb/n_gonal.rb
numb-0.20.0	lib/numb/n_gonal.rb