Ways to calc factorial with ruby

Days ago,i got a problem about how to calc factorial

Way 1 — the original way

def func(m)
	s = 1
	(1..m).each do |n|
		s *= n
	end
	s
end

Way 2 — less way

def func(m)
	return 1 if m == 1
	m*func(m-1)
end

Way 3 — ruby way

def func1(m)
	(1..m).inject {|s,i| s *= i}
end

Or

def func2(m)
	(1..m).inject :*
end