递归与尾递归：
%需要栈记录中间结果 factorial_1(1,1). factorial_1(N,F):- N > 1, NN is N - 1, factorial_1(NN,FF), F is N * FF. %不需要记录中间结果 factorial_2(1,F,F). factorial_2(N,T,F):- N > 1, TT is N * T, NN is N - 1, factorial_2(NN,TT,F).
?- factorial_1(5,X). X = 120 . ?- factorial_2(5,1,X). X = 120 .
%用栈记录中间结果 reverse_1([],[]). reverse_1([H|T],Rev):- reverse_1(T,TR), append(TR,[H],Rev). %借助变量记录中间结果 reverse_2([], Rev, Rev). reverse_2([H|T], Temp, Rev) :- reverse_2(T, [H|Temp], Rev).
?- reverse_1([a,b,c,d,e],X). X = [e, d, c, b, a]. ?- reverse_2([a,b,c,d,e],[],X). X = [e, d, c, b, a].