hw1.ml

let rec iter(n,f)=
	match (n,f) with
		| (0,f) ->(fun x->x)
		| (n,f) -> f iter(n-1,f)

let _ = print_int( iter(5,fun x->x+5) 3)

type nat = ZERO | SUCC of nat

let rec natadd (a,b) =
	match(a,b) with
		| (ZERO,ZERO) -> ZERO
		| (ZERO, b) -> b
		| (a, ZERO) -> a
		| (SUCC a', SUCC b') -> SUCC(natadd(a,b'))


let rec merge (l1,l2) = 
	match (l1,l2) with
		| ([], _) -> l2
		| (_, []) -> l1
		| (h1::t1, h2::t2) -> h1::h2::merge(t1,t2)

let rec natmul(a,b)=
	match(a,b) with
		| (ZERO,ZERO)->ZERO
		| (ZERO,b)->ZERO
		| (a,ZERO)->ZERO
		| (SUCC a', SUCC b') -> natadd(natmul(a,b'),a)


(*

let rec printer msg =
	match msg with
		| [] -> ()
		| h::t -> 
			print_int h;
			printer t
*)
(*let greeter = merge([1;2;3],[4;5;6])

let _ = printer greeter
*)

let rec sigma(a,b,f) =
	if a>b-1 then 0
	else f(b) + sigma(a,b-1,f)
(*
let _ = print_int(sigma(0,5,fun x->x+3))
*)