Question

- 下面给出的if else表示是否正确？

- 我希望if-else语句解释为：

如果成绩是NC且课程是CDC，则调用isNCinCDC或

如果成绩是NC并且课程是研讨会，那么请致电isNCinCDC或

如果成绩是NC而课程是论文，则调用isNCinCDC或

如果成绩是NC并且课程是选修课，那么请致电isNCinELEC或

如果成绩是NC，课程是练习学校，那么打电话给NinPS或

如果成绩是NC而课程是项目课程，那么请致电NinPC

isNCCalc([],[],[]) :-
display('There are no more courses to check for NC').

isNCCalc([G|T1],[S|T2],[C|T3]) :-
    (((G == 'NC' , C == 'CDC') -> isNCinCDC(S)) ;
    ((G == 'NC',C == 'SEMINAR'-> isNCinCDC(S)) ;
    ((G == 'NC',C == 'THESIS' -> isNCinCDC(S)) ;
    ((G == 'NC',C == 'ELECTIVES' -> isNCinELEC(S)) ;
    ((G == 'NC',C == 'PRACTICE SCHOOL' -> isNCinPS(S)) ;
    ((G == 'NC',C == 'PROJECT COURSE' -> isNCinPC(S)))),
    isNCCalc(T1,T2,T3).

Answer 1

你可以更简单地写它，因为

3 ?- display((a,b->c)).
->(,(a,b),c)
true.

4 ?- display(((a,b)->c)).
->(,(a,b),c)
true.

即。连词（逗号）绑定比暗示（箭头）更严格。然后

isNCCalc([G|T1],[S|T2],[C|T3]) :-
    (   G == 'NC', C == 'CDC'
    ->  isNCinCDC(S)
    ;   G == 'NC', C == 'SEMINAR'
    ->  isNCinCDC(S)
    ;   G == 'NC', C == 'THESIS'
    ->  isNCinCDC(S)
    ;   G == 'NC', C == 'ELECTIVES'
    ->  isNCinELEC(S)
    ;   G == 'NC', C == 'PRACTICE SCHOOL'
    ->  isNCinPS(S)
    ;   G == 'NC', C == 'PROJECT COURSE'
    ->  isNCinPC(S)
    ;   true
    ),
    isNCCalc(T1,T2,T3).

我添加了true作为最后一个选项，因为你可以在头部移动G =='NC'，并简化更多，或者当G \ ='NC'出现时，循环将完全失败。不确定，在这种情况下你没有指定你想要的东西。

Prolog条件制定

1 个答案: