prolog - Prolog 中的这个错误是什么意思？

Question

我正在 Prolog 中编写一个小程序来查找输入的国家/地区的首都，但我在第 10 行和第 11 行始终收到此错误:

错误:c:/users/cesar downs/documents/capital.pl:10:语法错误:需要运算符 错误:c:/users/cesar downs/documents/capital.pl:11:语法错误:需要运算符

我真的不明白，这是代码:

capital_of(guatemala, guatemala).
capital_of(tegucigalpa, honduras).
capital_of(san_salvador, el_salvador).
capital_of(managua, nicaragua).
capital_of(san_jose, costa_rica).
capital_of(panamá, panamá).

%Rules

Capital:- write(‘Enter the country: ‘),Read(Country),Answer(Country).
Answer(Country):- capital_of(Country,City),Write(‘The capital of: ‘),Write(Country),Write(‘ is ‘),Write(City).

Answer 1

顺便说一句，还可以考虑使用 format/2。例如，代替:

answer(Country) :-
    capital_of(Capital, Country),
    write('The capital of: '),
    write(Country),
    write(' is '),
    write(Capital).

你可以写:

answer(Country) :-
    capital_of(Capital, Country),
    format("The capital of: ~w is ~w", [Country,Capital]).