Factorial in Standard ML
This example shows the naive way to implement the factorial function. However, it is not tail recursive, since the recursive function call is not the only statement on the line. The
^ operator concatenates strings. The
Int.toString function converts integers into strings.
fun factorial n = if n <= 1 then 1 else factorial (n-1) * n; fun aux n = if n > 16 then () else ( print (Int.toString n ^ "! = " ^ Int.toString (factorial n) ^ "\n"); aux (n + 1) ); aux 0;