Answering a question asked on the Fb Learn Ruby Programming group

nqueens.rb

class Queen

  def initialize(arrayLength)    
    @array = Array.new(arrayLength)
  end
    
  def starter
    enumerate(@array,0)
  end

  def enumerate(q,n)
    if n == q.length
      printQueen(q)
    else
      for i in 0..(q.length-1)
        q[n] = i
        if isConsistent(q,n)
          enumerate(q,n+1)
        end
      end
    end

  end

  def isConsistent(q,n)
    n.times do |i|
      return false if (q[i] == q[n])
      return false if ((q[i] - q[n]) == (n-1) )
      return false if ((q[n] - q[i]) == (n-1) )
      return true
    end
  end

  def printQueen(q)
    for i in 0..(q.length-1)
      for j in 0..(q.length-1)
        if q[i] == j
          print "Q"
        else
          print "*"
        end
      end
      puts ""
    end
   puts ""
  end
end

queens = Queen.new(4)
queens.starter