Jane Street OCaml Challenge: Recursion
Functions in OCaml can call themselves — but only if marked with rec.
This will give a compilation error:
let add_every_number_up_to x =
assert (x >= 0);
match x with
| 0 -> 0
| _ -> x + add_every_number_up_to (x - 1)
Fix it by changing let to let rec.
Recursive Sum
This function sums all numbers up to x.
let rec add_every_number_up_to x =
assert (x >= 0);
match x with
| 0 -> 0
| _ -> x + add_every_number_up_to (x - 1)
Now You Try: Recursive Factorial
let rec factorial x =
assert (x >= 0);
failwith "For you to implement"
Tests for factorial
let%test "Testing factorial..." = Int.( = ) 1 (factorial 0)
let%test "Testing factorial..." = Int.( = ) 120 (factorial 5)
let%test "Testing factorial..." = Int.( = ) 479001600 (factorial 12)