以下代码和查询不起作用:
bottles(X) :-
write(X), write(' bottles of beer on the wall,'), nl,
write(X), write(' bottles of beer,'), nl,
write('Take one down, and pass it around,'), nl,
X1 is X - 1,
write(X1), write(' bottles of beer on the wall.'), nl,
bottles(X1).
bottles(1) :-
write('1 bottle of beer on the wall, 1 bottle of beer,'), nl,
write('Take one down, and pass it around,'), nl,
write('Now they are alle gone.'), nl.
?- bottles(99).
使用 Windows 上的 SWI-Prolog 8.3.15，我什至不能按 Ctrl-C。
出了什么问题？
最佳答案
它将始终保持递归，因为第一条规则从未规定 X 应该大于 1。因此，您可以通过以下方式修复此问题:
bottles(X) :-
<b>X > 1</b>, %% ← check that X is greater than one.
write(X), write(' bottles of beer on the wall,'), nl,
write(X), write(' bottles of beer,'), nl,
write('Take one down, and pass it around,'), nl,
X1 is X - 1,
write(X1), write(' bottles of beer on the wall.'), nl,
bottles(X1).
bottles(1) :-
write('1 bottle of beer on the wall, 1 bottle of beer,'), nl,
write('Take one down, and pass it around,'), nl,
write('Now they are alle gone.'), nl.关于prolog - Prolog 99瓶啤酒，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/65401793/