let l = [1;2;3;4;5];;
Printf.printf
"%B \n" mem l
3;
let rec mem
list element
= match list with | [] -> false
| head::body -> if head=element true else mem tail element;;
CmxldCBsID0gWzE7MjszOzQ7NV07OwpQcmludGYucHJpbnRmICIlQiBcbiIgbWVtIGwgMzsKCgpsZXQgcmVjIG1lbSBsaXN0IGVsZW1lbnQgPSBtYXRjaCBsaXN0IHdpdGggCgl8IFtdIC0+IGZhbHNlCgl8IGhlYWQ6OmJvZHkgLT4gaWYgaGVhZD1lbGVtZW50IHRydWUgZWxzZSBtZW0gdGFpbCBlbGVtZW50OzsKCgo=