菜单系统退出不按预期工作

Question

我在使用下面的代码时遇到问题。我尝试退出菜单时出错了。

   park(_,blue,basketball_court).
time(officehour,_) :- 
    menu2.

go :- start_message,menu1.
start_message :- 
    write('This is a program'),nl.

menu1 :-
    nl,write('Select operation:'),nl,
    write('1. Input time'),nl,
    write('2. Exit program'),nl,
    read(Y), choice1(Y).

choice1(1):-
    write('Place available to be parked:'),nl,
    write('Input time:'),nl,
    read(Y),
    repeat,
    time(Y,X),
    write(X),nl,
    fail,
    menu1.

choice1(2):-
    write('Exit program').


menu2 :- 
    nl,write('Select operation:'),nl,
    write('1. Check which parking area available to park right now.'),nl,
    write('2. Check whether a particular parking area is legal to park.'),nl,
    write('3. End program.'),nl,
    read(X),nl,choice(X).

choice(2):-
    write('Enter your identity:'),nl,
    read(C),
    write('Enter sticker type:'),nl,
    read(D),
    write('Enter parking area:'),nl,
    read(E),
    park(C,D,E),
    menu2.

choice(3):- 
    write('Exit program.').

以上是上述代码运行时的结果...正如您所看到的，我想看到的是Exit program. True，而不是如下所示。

This is a program
Input time:
officehour
Place available to be parked:

Select operation:
1. Check which parking area available to park right now.
2. Check whether a particular parking area is legal to park.
3. End program.
3

Exit program._896

Select operation:
1. Check which parking area available to park right now.
2. Check whether a particular parking area is legal to park.
3. End program.

从这里忽略。我只是打字以满足发布.....

的要求