OCAML
let pole (a,b,c) =
  let
    abs x =
     if(x<0.) then -.x
     else x
  and
     p = (a+.b+.c)/.2.
  in
    if(abs(b-.c)<a && a<(b+.c)) then sqrt (p*.(p-.a)*.(p-.b)*.(p-.c))
    else raise (Failure "Nie da sie zbudowac trojkata");;

OZ...
declare fun {Zad1 A#B#C}
	   local fun {Abs X}
		    if X<0 then -X
		    else X end
		 end