Prolog

/* Lab 2 */
sum(N,D,F):-D>N,F is N.
sum(N,D,F):-N>0,N1 is N-D,sum(N1,D,F1),F is (N1+D)+F1.
fact(N,F):-N=1,F is 1.
fact(N,F):-N1 is N-1, fact(N1, F1), F is N*F1.
result:-write("Enter N= "), read(N), N>0, fact(N,F), write("Fact= "), writeln(F).

/* Lab 3 */
first([X|_], F):- F=X.

last([HEAD|[]], F):- F=HEAD.
last([_|Y], F):-last(Y, F1), F=F1.


cutTo([X,TAIL], TAIL, F):-F=X.
cutTo([X|_], _, F):-F = [X|F].
deleteLast([_|[]], F):-F=[].
deleteLast([X|BODY], F):-deleteLast(BODY, F1), F=[X|F1].

result:-
    first([1,2,3], F1), writeln(F1),
    last([1,2,3], F2), writeln(F2),
    deleteLast([1,2,3], F3), writeln(F3).