prolog - 我正在使用古老的涡轮序言。并在以下代码 :- mis-spelling or not declared predicate 中不断面临错误

Question

domains
    A,B,C = symbol
    N,P = integer

predicates
    tower(integer,symbol,symbol,symbol,integer)

    go

clauses
    go :- clearwindow,
          write("enter value of N (For Transfering from A To B)"),
          readint(N),
          tower(N,'a','b','c',N).

    tower(N,A,B,C,P):-
        N > 1,
        P is N-1
        tower(P,A,C,B,P),
        write([move , A,B]),nl,
        tower(P,C,B,A,P).

        tower(0,_,_,_):- !.

Answer 1

您在 P is N-1 后面缺少一个逗号.