Sweet ass factorials in Ruby! #1 - Iterative long #2 - Iterative short #3 - Recursive long #4 - Recursive short

factorial.rb

# Factorial Recursive #
#######################

# Long Version:

def factorial(n)
  if n == 0
    return 1
  else 
    return n*factorial(n-1)
  end
end


# Short Version (with ternary operator :D):

def factorial(n)
  n == 0 ? 1 : n*factorial(n-1)
end



# Factorial Iterative #
#######################


# Long Version:

def factorial(n)
  sum = 1
  until n == 0
    sum *= n
    n -= 1
  end
 sum
end


# Oh so sweet short version:

def factorial(n)
  (1..n).inject(:*) || 1
end