hex(X,W) :- X =:= 0, W=[],!.
hex(X,W) :- X1 is div(X,16),
            X2 is mod(X,16),
            hex(X1,T2),
            append(T2,[X2],W).

zamiana2(L1,L2) :-  L1=[], L2=[].
zamiana2(L1,L2) :- L1=[H|T],

    H=:=10,H2='A',
   zamiana2(T,T2), L2=[H2|T2].


zamiana2(L1,L2) :- L1=[H|T],

    H=:=11,H2='B',
   zamiana2(T,T2), L2=[H2|T2].


zamiana2(L1,L2) :- L1=[H|T],

    H=:=12,H2='C',
   zamiana2(T,T2), L2=[H2|T2].


zamiana2(L1,L2) :- L1=[H|T],

    H=:=13,H2='D',
   zamiana2(T,T2), L2=[H2|T2].


zamiana2(L1,L2) :- L1=[H|T],

    H=:=14,H2='E',
   zamiana2(T,T2), L2=[H2|T2].

zamiana2(L1,L2) :- L1=[H|T],

    H=:=15,H2='F',
   zamiana2(T,T2), L2=[H2|T2].


zamiana2(L1,L2) :- L1=[H|T],

    H<10,
    zamiana2(T,T2), L2=[H|T2].


zamiana2(L1,L2) :- L1=[H|T],

    H>15,
    zamiana2(T,T2), L2=[H|T2].


hextru(X,W) :- hex(X,WH), zamiana2(WH,W).