Many faces of Factorial in Elixir

fact.exs

defmodule Foo do

  # Use case matching
  def fact1(n) do
    case n do
      1 -> 1
      _ -> n * fact1(n-1)
    end
  end

  # Use conditionals
  def fact2(n) do
    if n == 1 do
      1
    else
      n * fact2(n-1)
    end
  end

  # Use reduce
  def fact3(n) do
    Enum.reduce(1..n, 1, &(&1 * &2))
  end

  # Use reduce with anonymous function
  def fact4(n) do
    Enum.reduce(1..n, 1, fn(a,b) -> a * b; end)
  end

  # Use pattern matching
  def fact5(1), do: 1
  def fact5(n), do: n * fact5(n-1)
end

IO.puts Foo.fact1(5)
IO.puts Foo.fact2(5)
IO.puts Foo.fact3(5)
IO.puts Foo.fact4(5)
IO.puts Foo.fact5(5)