someFns.rb

#!/usr/bin/env ruby

# Factorials
def fact(n)
  return 1 if n == 1

  fact(n - 1) * n
end

def factReduce(n)
  (1..n).reduce(:*)
end

def factInject(n)
  (1..n).inject { |sum, c| sum * c }
end

def factIter(n)
  fact = 1

  n.times { |c| fact = fact * (c + 1) }
  fact
end

# Factorials

puts fact 2
puts fact 3
puts fact 4
puts fact 5
puts fact 6
puts fact 7