Factorial in Icon

Example for versions iconc 9.4

This example uses recursive factorial definition. 0 to 16 is a generator which returns all integers between 0 and 16, inclusive. every ... do allows to fetch every result returned by the generator and process it (calculate factorial and perform write). 

procedure factorial (n)
   if n = 0 then
      return 1
   else if n > 0 then
      return n * factorial (n - 1)
end

procedure main ()
   local i
   every i := 0 to 16 do
      write (i, "! = ", factorial (i))
end