(* function to compute list length *)
fun prob1 nil = 0
|	prob1 (h::t) = 1 + prob1(t);
(* function to return next to last item in list or nil if length = 1 or 0 *)
fun prob2 nil = []
|	prob2 [x] = []
|	prob2 [x,y] = [x]
|	prob2 (h::t) = prob2(t);
(* function to compute number of even integers *)
fun prob3 nil = 0
|	prob3(h::t) = if h mod 2 = 0 then 1 + prob3(t) else 0 + prob3(t);
(* function to add min and max integers in a list *)
fun min nil = 0
|	min [x] = x
|	min (h::t) = Int.min(h, min(t)); 
fun max nil = 0
|	max [x] = x
|       max (h::t) = Int.max(h, max(t)); 
fun prob4 [] = 0 
|	prob4(x) = min(x) + max(x);
(* function to create a list of doublets from original list *)
fun prob5 nil = []
|	prob5 [x] = [x,x]
|	prob5(h::t) = [h,h]@prob5(t);
(* function to remove I'th item from list *)
(* fun prob6 (h::t,i : int) = if i=1 then t else [h,prob6(t,i-1)]; *)
fun loop(i) = i-1;
fun listloop(h::t, i : int) = if i=1 then h::t else t;  
fun prob6(h::t,i : int) = if loop(i)=1 then listloop(t,0) else 
prob6(listloop(h::t,1),loop(i));